You can easily make it 2 clicks:

1. Open Settings
2. Go to "Power"
3. Change the "Power button action" dropdown to "Power off"

Now click the physical power button on your device and then select power off from the prompt - that is 2 clicks (1 if you don't count pressing the power button as a click).

Reduce by two clicks

Option 1) Install the Poweroff Button on Topbar extension by Darknico. It adds a separate Power button on the right of the top bar.

Option 2) Create a "regular" launcher for "Power Off" (with thanks to pomsky). Either:

• Pin that launcher to the dock.
• Pin that launcher to the top panel using the Frippery Panel Favorites extension.

You may reduce with one more click by substituting the command in the launcher with "poweroff". Then, a single click on the launcher will immediately shut down the machine without confirmation dialog.

Reduce by one click

Option 3) Use the extension Bring Out Submenu Of Power Off/Logout Button by Pratap, or Simpler Off Menu by K3rcus. These extensions bring the items in the "Power Off/Log Out" submenu directly into the system menu, allowing to access them with one less click.

Getting it down to 1 "click" (technically a button press):

By default, ubuntu shuts down the machine when you press the power button.

Then just wait 60 seconds for the machine to power off instead of clicking again.

I have the habit of creating my own keyboard shortcut to shutdown the PC because this is lot easier and less painful.

I have used too many buttons to avoid any accidental shutdown.

You can decrease it and make it like Super+P or something like that if you are careful enough.

The answer is 0.

Install KShutdown, specify how long are you going to be online. As long as you stick to the plan and not mess with the time and save whatever you're doing 2 minutes prior. The machine will turn itself off, without you even touching it.

If you want to write your own command, start the terminal and type:

sudo shutdown -h +30

+30 (minutes) is an example. Change it to however long you want to stay online. And if you want the machine to turn itself off at a specific time, try:

sudo shutdown -h 20:30

(time is hypothetical, change it to whatever you want).

Note: Without the -h or -r switch it isn't a valid command.

0 clicks, a few clacks.

An alternative solution that doesn't require a mouse (just keyboard):

1. Press and hold Ctrl+ALT+t

This brings up a terminal window.

2. Type "poweroff" then hit the Enter key.

Sony TV remote suspends laptop via network control

tvpowered (TV controls power to the computer) is a bash script that automatically suspends laptop when Sony Bravia TV is powered off. Additionally it will:

• Turn off picture of TV to save power when you are not watching movies on TV.
• Display pop-up bubble when you change volume of TV used for listening to music.

Please note this only works with Sony Bravia TVs.

Overview

When TV is turned off tvpowered automatically suspends, hibernates or powers off the laptop. Change the setting of SCTL global variable to control which action is taken.

tvpowered should be run as a normal user and called in Startup Applications.

Program design is straight forward:

1. Wait for TV to be powered on.
2. Begin fully active operation.
3. Check if TV is powered off. If off go to step 5.
4. Sleep for 3 seconds and repeat step 3.
5. Suspend or Poweroff system when TV is powered off.
6. If resuming from suspend go back to step 1.

In between these steps pop-up bubble messages appear on Desktop and are also logged to journalctl:

$ journalctl -xe | grep tvpower

Jun 11 18:11:20 tvpowered[27398]: TV is powered on. 'tvpowered' is now waiting for TV to power off.
Jun 11 18:11:47 tvpowered[28229]: TV Powered off. 'systemctl suspend' being called.
Jun 11 18:11:47 tvpowered[28238]: System powered back up. Checking if TV powered on. './tvpowered'.
Jun 11 18:12:26 tvpowered[31672]: TV is powered on. 'tvpowered' is now waiting for TV to power off.

tvpowered script

Copy and paste the script into a file on your computer and mark it executable with:

chmod a+x /path/to/tvpowered

Where /path/to/ is the directory name you created the file in.

You can also user your file manager (like Nautilus) to make the file executable.

In the script below there are a few constants you will need to set:

SCTL=suspend        # systemctl paramater: suspend or poweroff
IP=192.168.0.16     # IP address for Sony TV
PWRD=123            # Password for Sony TV IP Connect

tvpowered complete bash script

#!/bin/bash

# NAME: tvpowered
#
#       Original name slave2tv announced as politically incorrect after one day:
#       https://www.rt.com/news/491343-microsoft-coding-blacklists-slaves/
#
# DESC: When TV is powered off automatically suspend the laptop.
# DATE: June 9, 2020. Modified December 31, 2020
#
# NOTE: Written for Ask Ubuntu question:
#       https://askubuntu.com/questions/1247484/
#       4-clicks-to-shut-down-ubuntu-can-we-reduce-this

# UPDT: Jun 10 2020: Make name politically correct for Microsoft guidelines.
#       Change name from 'slave2tv' to 'tvpowered'. Abandon approach of polling
#       i2c, drm, i915, nvidia, xrandr, etc to see if monitor turned off. Setup
#       WiFi on TV instead and use Sony REST API to communicate TV status.

#       Jun 11 2020: Add pop-up bubble status messages. Add dependencies.
#       Add TenMinuteSpam. Add WaitUserSignOn. Add $SCTL constant. Convert
#       in-line code to mainline format.

#       Oct 03 2020: If ethernet disconnected we don't want to suspend.
#       Add TenMinuteSpam. Add WaitUserSignOn. Add $SCTL constant. Convert
#       in-line code to mainline format.

#       Oct 18 2020: If WiFi disconnected we don't want to suspend.

#       Dec 23 2020: After resume turn off picture with power savings.

#       Dec 31 2020: Fast popping bubble messages when volume changes.

# Sources:

# https://gist.github.com/kalleth/e10e8f3b8b7cb1bac21463b0073a65fb#cec-sonycec
# https://pro-bravia.sony.net/develop/integrate/rest-api/spec/service/audio/v1_0/setAudioVolume/index.html
# https://developer.sony.com/develop/audio-control-api/get-started/http-example#tutorial-step-2
# https://en.wikipedia.org/wiki/CURL
# https://stackoverflow.com/questions/7172784/how-do-i-post-json-data-with-curl
# https://stackoverflow.com/questions/2829613/how-do-you-tell-if-a-string-contains-another-string-in-posix-sh

SCTL=suspend        # systemctl paramater: suspend or poweroff
IP=192.168.0.16     # IP address for Sony TV
PWRD=123            # Password for Sony TV IP Connect (Pre-Shared key)

# Must have curl package.
command -v curl >/dev/null 2>&1 || { echo >&2 \
        "'curl' package required but it is not installed.  Aborting."; \
        exit 2; }

# Must have notify-send from libnotify-bin package
command -v notify-send >/dev/null 2>&1 || { echo >&2 \
        "libnotify-bin package required but it is not installed.  Aborting."; \
        exit 3; }

cURLit () {

    # $1 = JSON String in pretty format converted to file for cURL --data.
    # $2 = Sony subsystem to talk to, eg accessControl, audio, system, etc.
    # 3  = variable name to receive reply from TV

    local TEMP Result ReturnState

    # Declare mathres as reference to argument 3 provided (Bash 4.3 or greater)
    declare -n Result=$3  # ERROR: declare: `': not a valid identifier

    # Create temporary file in RAM for curl command
    TEMP=$(mktemp --tmpdir json.XXXXXXXX)
    echo "$1" > "$TEMP"

    # -s = silent
    Result=$(curl -s -H "Content-Type: application/json; charset=UTF-8" \
             -H "X-Auth-PSK: $PWRD" \
             --data @"$TEMP" \
             http://$IP/sony/"$2")
#echo "Result: $Result"    # Remove leading # for debugging
    ReturnState="$?"
    # TO-DO: check $? and if non-zero pop up dialog with $TEMP contents
    rm "$TEMP"

} # cURLit

GetPowerStatus () {

    local Reply ReturnState

    # Copy and paste JSON strings from Sony website: 
    # https://pro-bravia.sony.net/develop/integrate/rest-api/spec/service/system/v1_0/getPowerStatus/index.html
    JSONstr='{
                "method": "getPowerStatus",
                "id": 50,
                "params": [],
                "version": "1.0"
             }'

    cURLit "$JSONstr" "system" Reply    # No $ for Reply variable! pass pointer
    ReturnState="$?"

#echo "Reply: $Reply"    # Remove leading # for debugging
    # Reply: {"result":[{"status":"active"}],"id":50}
    #    or: {"result":[{"status":"standby"}],"id":50}

    # Does 'active' substring exist in TV's reply?
    [[ "${Reply#*active}" != "$Reply" ]] && return 0

    # TV is turned off
    # Might want timer tests to make sure we aren't repeatedly turning off
    return 1
    
} # GetPowerStatus

GetVolume () {

    # Copy and paste JSON strings from Sony website: 
    # https://pro-bravia.sony.net/develop/integrate/rest-api/spec/service/audio/v1_0/getVolumeInformation/index.html
    JSONstr='{
                "method": "getVolumeInformation",
                "id": 33,
                "params": [],
                "version": "1.0"
             }'
    
    # Then pass string to cURL for execution
    cURLit "$JSONstr" "audio" Reply

    # Sample output:
    #   Volume:, {"result":[[{"target":"speaker","volume":44,"mute":false,
    #   "maxVolume":100,"minVolume":0},{"target":"headphone","volume":15,
    #   "mute":false,"maxVolume":100,"minVolume":0}]],"id":33}

    Start="${Reply:41:4}"
    Volume=${Start%,*}

    return $Volume

} # GetVolume


log () {
    logger --id=$$ -t "tvpowered" "$1"
} # log


WaitForSignOn () {

    # tvpowered might be loaded during boot. The user name is required
    # for sending popup bubble messages and dialogs to screen. We must
    # wait until user signs on to get .Xauthority file settings.

    # code lifted from eyesome.sh
    SpamOn=10       # Causes 10 iterations of 2 second sleep
    SpamContext="Login"
    TotalWait=0

    # Wait for user to sign on then get Xserver access for xrandr calls
    UserName=""
    while [[ $UserName == "" ]]; do

        # Find UserName currently logged in.
        UserName="$(who -u | grep -F '(:0)' | head -n 1 | awk '{print $1}')"
        [[ $UserName != "" ]] && break

        sleep "$SpamLength"
        TotalWait=$(( TotalWait + SpamLength ))
    done

    if [[ $TotalWait != "0" ]] ; then
        log "Waited $TotalWait seconds for $UserName to login."
        xhost local:root
        export XAUTHORITY="/home/$UserName/.Xauthority"
    fi

} # WaitForSignOn


LastVolume=0
CurrVolume=0


TenMinuteSpam () {

    # If TV not powered up Spam user for 10 minutes that 'tvpowered' is running
    # and will shut down / suspend system

    WaitForSignOn   # Might be called by root during boot before user signed on.

    Cnt=0
    while : ; do

        GetPowerStatus
        if [[ "$?" == "0" ]] ; then
            log "TV is powered on. 'tvpowered' is now waiting for TV to power off."
            break
        else
            # Spam user every 60 seconds
            (( $(( Cnt % 20 )) == 0 )) && \
                notify-send --urgency=critical "tvpowered" \
                    -h string:x-canonical-private-synchronous:startup \
                    --icon=/usr/share/icons/gnome/48x48/devices/display.png \
                    "TV not communicating.\n Checking TV again..."
        fi
        sleep 3
        (( Cnt++ ))
    done
    
    GetVolume
    LastVolume="$?"
    notify-send --urgency=critical "tvpowered" \
        --icon=/usr/share/icons/gnome/48x48/devices/display.png \
        "Fully activated.\n System will $SCTL when TV powered off.  Volume: $LastVolume"
    
    return 0

} # TenMinuteSpam

###################################
#            MAINLINE             #
###################################

Main () {

    echo "$0: Initialization. Ensuring TV is powered on before starting."
    TenMinuteSpam
    echo "$0: Fully activated. Waiting for TV to powered off and then $SCTL."
    echo "$0: LastVolume: $LastVolume"

    Cnt=0
    FirstTime=true
    VolumeCnt=0             # TV Remote changed volume, so shrorter sleep

    while : ; do
        #etherup=$(cat /sys/class/net/e*/carrier) # Returns 1 even disconnected
        #wifi_up=$(cat /sys/class/net/w*/carrier)
        #if [[ $etherup <> "1" && $wifi_up <> "1" ]] ; then
        state=$(nmcli -f STATE -t g)            # Network manager takes .5 CPU
        if [[ $state == disconnected ]] ; then
            # Spam user every 60 * Cot seconds
            notify-send --urgency=critical "tvpowered" \
                -h string:x-canonical-private-synchronous:startup \
                --icon=/usr/share/icons/gnome/48x48/devices/display.png \
                "Internet not up.\nChecking Ethernet and/or  WiFi state again..."
            sleep $((Cnt * 60))
            (( Cnt++ ))
            continue
        else
            Cnt=0                               # Reset timer for next loop
        fi

        GetPowerStatus
        if [[ "$?" != "0" ]] ; then
            state=$(nmcli -f STATE -t g)        # Network manager takes .5 CPU
            if [[ $state == disconnected ]] ; then
                echo "Unexpected disconnect, aborting suspend."
            else
                log "TV Powered off. 'systemctl $SCTL' being called."
                systemctl "$SCTL"
                log "System powered back up. Checking if TV powered on. '$0'."
                sleep 10 #  Give system time to wake from suspend
                TenMinuteSpam
                /home/rick/sony/pictureoff.sh
            fi
        fi

        GetVolume
        CurrVolume="$?"
        # echo CurrVolume: $CurrVolume LastVolume: $LastVolume

        if [[ "$CurrVolume" != "$LastVolume" ]] ; then
            # Ask Ubuntu: https://askubuntu.com/a/871207/307523
            notify-send --urgency=critical "tvpowered" \
                -h string:x-canonical-private-synchronous:volume \
                --icon=/usr/share/icons/gnome/48x48/devices/audio-speakers.png \
                "Volume: $CurrVolume"
            LastVolume=$CurrVolume
            VolumeCnt=10
            # TODO: Process VolumeCnt internally in loop instead of larger loop
        fi

        if [[ $VolumeCnt > 0 ]]; then
            (( VolumeCnt-- ))
            SleepTime=.01
        else
            SleepTime=2.5
        fi

        sleep $SleepTime

        # Next iteration
        FirstTime=false
    done

    exit 0

} # Main

Main "$@"

Summary

I was inspired by OP's question and never realized how cumbersome and time-consuming my end of day suspend process used to be:

1. Find where the cursor is on on one of three monitors
2. Navigate to top right of whichever monitor and left click Cog menu
3. Pull mouse down to suspend option
4. Click suspend (being careful not to click shutdown next to it!)
5. Power off Sony TV
6. Power off Toshiba TV

tvpowered has eliminated time consuming steps 1. through 4.

Bonus - Turn of Light Behind TV

For nighttime viewing, there is a light behind the TV. Whenever the laptop goes to sleep, it first shuts off the light.

Create the script /etc/NetworkManager/dispatcher.d/pre-down.d/smartplug_off and place into it:

#!/bin/bash

# NAME: smartplug_off
# PATH: /etc/NetworkManager/dispatcher.d/pre-down.d
# DESC: Turn off smartplug light power for TV light
# DATE: March 7, 2020.

# CALL: Called by Network Manager before going down. Network manager in turn
#       is called by systemd during suspend/hibernate/shutdown

# NOTE: myisp.sh and hs100.sh must be installed for hs100 tp-link power plug.
#       https://developer.gnome.org/NetworkManager/stable/NetworkManager.html

PlugName="192.168.0.15"

status=$(hs100.sh -i "$PlugName" check | cut -f2)
if [ $status == "OFF" ] ; then
    : # Nothing to do already off
elif [ $status == "ON" ] ; then
    hs100.sh -i "$PlugName" off
else
    echo Error hs100.sh not responding check connection and IP "$PlugName".
fi

I have a laptop by my television that I access with a wireless keyboard/touchpad device. I also keep the lid closed as well.

What I did is add a simple gnome extension called Gnome-Shutdown-Button. You can find a ton of these extensions at https://extensions.gnome.org/

It opens a dialogue that says "shutting down in 30 seconds" (it might be less) and offers a second option to shut down now.

in terminal shutdown now do the trick for me