On Ubuntu 20.04 (Lenovo Thinkpad), display scale of 100% is tiny, 200% is still small

Ubuntu does not know the size of your screen and thus does not know about its pixel density.

For example on a 15" screen 100% might be tiny, but on a 32" screen with the same resolution 100% would fit just fine. That is why you can change the scaling to fit your screen size manually.

Your Lenovo laptop has a higher pixel density than your Dell Laptop.

Workaround

run the below command when fractional scale is not enabled.

gdbus call --session --dest org.gnome.Mutter.DisplayConfig --object-path /org/gnome/Mutter/DisplayConfig --method org.gnome.Mutter.DisplayConfig.GetCurrentState

Example:

$ gdbus call --session --dest org.gnome.Mutter.DisplayConfig --object-path /org/gnome/Mutter/DisplayConfig --method org.gnome.Mutter.DisplayConfig.GetCurrentState
(uint32 7, [(('eDP-1-1', 'SDC', '0x4141', '0x00000000'), [('[email protected]', 1366, 768, 59.998008728027344, 1.0, [1.0, 2.0], {'is-preferred': <true>}), ('[email protected]', 1360, 768, 59.798992156982422, 1.0, [1.0, 2.0], {}), ('[email protected]', 1360, 768, 59.960025787353516, 1.0, [1.0, 2.0], {'is-current': <true>}), ('[email protected]', 1280, 720, 120.00162506103516, 1.0, [1.0, 2.0], {}), ('[email protected]', 1280, 720, 119.98211669921875, 1.0, [1.0, 2.0], {}), ('[email protected]', 1280, 720, 59.855125427246094, 1.0, [1.0, 2.0], {}), ('[email protected]', 1280, 720, 59.744712829589844, 1.0, [1.0, 2.0], {}), ('[email protected]', 1024, 768, 120.07466888427734, 1.0, [1.0], {}), ('[email protected]', 1024, 768, 60.003841400146484, 1.0, [1.0], {}), ('960x720@120', 960, 720, 120.0, 1.0, [1.0], {}), ('[email protected]', 928, 696, 120.101318359375, 1.0, [1.0], {}), ('[email protected]', 896, 672, 120.02888488769531, 1.0, [1.0], {}), ('[email protected]', 1024, 576, 119.90670776367188, 1.0, [1.0], {}), ('[email protected]', 1024, 576, 119.91866302490234, 1.0, [1.0], {}), ('[email protected]', 1024, 576, 59.899215698242188, 1.0, [1.0], {}), ('[email protected]', 1024, 576, 59.819515228271484, 1.0, [1.0], {}), ('[email protected]', 960, 600, 119.865478515625, 1.0, [1.0], {}), ('[email protected]', 960, 600, 119.99750518798828, 1.0, [1.0], {}), ('[email protected]', 960, 540, 119.92568969726562, 1.0, [1.0], {}), ('[email protected]', 960, 540, 119.97574615478516, 1.0, [1.0], {}), ('[email protected]', 960, 540, 59.6290283203125, 1.0, [1.0], {}), ('[email protected]', 960, 540, 59.818218231201172, 1.0, [1.0], {}), ('800x600@120', 800, 600, 120.0, 1.0, [1.0], {}), ('[email protected]', 800, 600, 60.316539764404297, 1.0, [1.0], {}), ('[email protected]', 800, 600, 56.25, 1.0, [1.0], {}), ('[email protected]', 840, 525, 120.01870727539062, 1.0, [1.0], {}), ('[email protected]', 840, 525, 119.76650238037109, 1.0, [1.0], {}), ('[email protected]', 864, 486, 59.91534423828125, 1.0, [1.0], {}), ('[email protected]', 864, 486, 59.5703125, 1.0, [1.0], {}), ('[email protected]', 800, 512, 120.33700561523438, 1.0, [1.0], {})], {'is-builtin': <true>, 'display-name': <'Built-in display'>})], [(0, 0, 1.0, uint32 0, true, [('eDP-1-1', 'SDC', '0x4141', '0x00000000')], @a{sv} {})], {'renderer': <'xrandr'>, 'layout-mode': <uint32 2>, 'global-scale-required': <true>, 'legacy-ui-scaling-factor': <1>, 'max-screen-size': <(16384, 16384)>})
$

from the above result, note that at the start of the output "(unit32 7" the value 7 varies and it is very important. Note that value in your case.

Next read the common pattern with many different values.. like this

'[email protected]', 1366, 768, 59.998008728027344, 1.0, [1.0, 2.0]

[email protected]: mode ID
1366: width in physical pixels
768: height in physical pixels
59.998008728027344: refresh rate
1.0: scale preferred as per calculations
[1.0, 2.0]: scales supported by the above mode ([email protected])

This means that out of the available modes..( there are plenty of modes as per the output ) If you choose [email protected] this mode.. you have only two scales available [1.0, 2.0]

Now enable the fractional scale and run the command again..

$ gdbus call --session --dest org.gnome.Mutter.DisplayConfig --object-path /org/gnome/Mutter/DisplayConfig --method org.gnome.Mutter.DisplayConfig.GetCurrentState
(uint32 7, [(('eDP-1-1', 'SDC', '0x4141', '0x00000000'), [('[email protected]', 1366, 768, 59.998008728027344, 1.0, [1.0, 2.0], {'is-preferred': <true>}), ('[email protected]', 1360, 768, 59.798992156982422, 1.0, [1.0, 1.2307692766189575, 1.4545454978942871, 1.7777777910232544, 2.0], {}), ('[email protected]', 1360, 768, 59.960025787353516, 1.0, [1.0, 1.2307692766189575, 1.4545454978942871, 1.7777777910232544, 2.0], {'is-current': <true>}), ('[email protected]', 1280, 720, 120.00162506103516, 1.0, [1.0, 1.25, 1.5094339847564697, 1.7391303777694702, 2.0], {}), ('[email protected]', 1280, 720, 119.98211669921875, 1.0, [1.0, 1.25, 1.5094339847564697, 1.7391303777694702, 2.0], {}), ('[email protected]', 1280, 720, 59.855125427246094, 1.0, [1.0, 1.25, 1.5094339847564697, 1.7391303777694702, 2.0], {}), ('[email protected]', 1280, 720, 59.744712829589844, 1.0, [1.0, 1.25, 1.5094339847564697, 1.7391303777694702, 2.0], {}), ('[email protected]', 1024, 768, 120.07466888427734, 1.0, [1.0, 1.2487804889678955, 1.4970760345458984], {}), ('[email protected]', 1024, 768, 60.003841400146484, 1.0, [1.0, 1.2487804889678955, 1.4970760345458984], {}), ('960x720@120', 960, 720, 120.0, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 928, 696, 120.101318359375, 1.0, [1.0, 1.2473118305206299], {}), ('[email protected]', 896, 672, 120.02888488769531, 1.0, [1.0, 1.251396656036377], {}), ('[email protected]', 1024, 576, 119.90670776367188, 1.0, [1.0, 1.2799999713897705, 1.4883720874786377], {}), ('[email protected]', 1024, 576, 119.91866302490234, 1.0, [1.0, 1.2799999713897705, 1.4883720874786377], {}), ('[email protected]', 1024, 576, 59.899215698242188, 1.0, [1.0, 1.2799999713897705, 1.4883720874786377], {}), ('[email protected]', 1024, 576, 59.819515228271484, 1.0, [1.0, 1.2799999713897705, 1.4883720874786377], {}), ('[email protected]', 960, 600, 119.865478515625, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 960, 600, 119.99750518798828, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 960, 540, 119.92568969726562, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 960, 540, 119.97574615478516, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 960, 540, 59.6290283203125, 1.0, [1.0, 1.25, 1.5], {}), ('[email protected]', 960, 540, 59.818218231201172, 1.0, [1.0, 1.25, 1.5], {}), ('800x600@120', 800, 600, 120.0, 1.0, [1.0, 1.25], {}), ('[email protected]', 800, 600, 60.316539764404297, 1.0, [1.0, 1.25], {}), ('[email protected]', 800, 600, 56.25, 1.0, [1.0, 1.25], {}), ('[email protected]', 840, 525, 120.01870727539062, 1.0, [1.0, 1.25], {}), ('[email protected]', 840, 525, 119.76650238037109, 1.0, [1.0, 1.25], {}), ('[email protected]', 864, 486, 59.91534423828125, 1.0, [1.0, 1.2558139562606812], {}), ('[email protected]', 864, 486, 59.5703125, 1.0, [1.0, 1.2558139562606812], {}), ('[email protected]', 800, 512, 120.33700561523438, 1.0, [1.0, 1.2799999713897705], {})], {'is-builtin': <true>, 'display-name': <'Built-in display'>})], [(0, 0, 1.0, uint32 0, true, [('eDP-1-1', 'SDC', '0x4141', '0x00000000')], @a{sv} {})], {'renderer': <'xrandr'>, 'layout-mode': <uint32 3>, 'supports-changing-layout-mode': <true>, 'x11-fractional-scaling': <true>, 'legacy-ui-scaling-factor': <1>, 'max-screen-size': <(16384, 16384)>})
$

This time observe the lines again,

'[email protected]', 1360, 768, 59.960025787353516, 1.0, [1.0, 1.2307692766189575, 1.4545454978942871, 1.7777777910232544, 2.0]

Observe that now available scales are changed. this means you can set from the above output 1.23.......... or 1.45.......... or 1.77....... or 2.0

Since my laptop is 1366x768 it has less scales available.. but when I connect it to my 4K TV.. I will have more available scales.. In your case.. your laptop is hi pixelated, you will have the more options for your desired resolution 3840x2168

So first run the command

gdbus call --session --dest org.gnome.Mutter.DisplayConfig --object-path /org/gnome/Mutter/DisplayConfig --method org.gnome.Mutter.DisplayConfig.GetCurrentState

and note down the values

for example:

1. 7 in Unit32 7 at the start of the output of the above command

2. [email protected] in the preferred mode and which suits the nearly required scale

Example line of my requirement:

('[email protected]', 1360, 768, 59.798992156982422, 1.0, [1.0, 1.2307692766189575, 1.4545454978942871, 1.7777777910232544, 2.0]

3. 1.7777777910232544 is the scale which I preferred out of the available for example..

4. eDP-1-1 this is my Display Change this in your case.

Now to set the scale, in your case you will definitely have 2.25 or 2.50 nearly equivalent values.. edit the below command to suit your values..

gdbus call --session --dest org.gnome.Mutter.DisplayConfig --object-path /org/gnome/Mutter/DisplayConfig --method org.gnome.Mutter.DisplayConfig.ApplyMonitorsConfig 7 1 "[(0, 0, 1.7777777910232544, 0, true, [('eDP-1-1', '[email protected]', [] )] )]" "[]"

The explanation of the above command and source is available https://unix.stackexchange.com

Successful command example: below gif cant show you accurately but the result is fine in my case..