'No WiFi Adapter Found" even with driver running

A few weeks ago, my wifi signal was bad. I've set a few options in /etc/modprobe.d/ath9k.conf and I've got a little improvement. Now my signal started again to drop randomly, and I've tried to install backport-iwlwifi. Now the Wifi icon doesn't appear at all, and when I check 'settings -> Wifi' I get the following message: No WiFi Adapter Found.

When I try sudo modprobe -r ath9k I get modprobe: FATAL: Module ath9k is in use. That has never happened to me.

I've tried to reinstall ath9k and Linux firmware, but it didn't work.

My Linux: 5.3.0-51-generic #44~18.04.2-Ubuntu SMP Thu Apr 23 14:27:18 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux.

I don't know what info may help, so here are a few of them:

Output of ifconfig:

enp7s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.100  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::adb6:b0b5:d21d:6170  prefixlen 64  scopeid 0x20<link>
        ether f4:8e:38:e7:00:47  txqueuelen 1000  (Ethernet)
        RX packets 76950  bytes 79761945 (79.7 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 73083  bytes 17147217 (17.1 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 11732  bytes 1151613 (1.1 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 11732  bytes 1151613 (1.1 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Output of sudo lshw -C network:

  *-network                 
       description: Network controller
       product: QCA9565 / AR9565 Wireless Network Adapter
       vendor: Qualcomm Atheros
       physical id: 0
       bus info: pci@0000:06:00.0
       version: 01
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list rom
       configuration: driver=ath9k latency=0
       resources: irq:18 memory:f7100000-f717ffff memory:f7180000-f718ffff
  *-network
       description: Ethernet interface
       product: RTL810xE PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:07:00.0
       logical name: enp7s0
       version: 07
       serial: f4:8e:38:e7:00:47
       size: 10Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 duplex=full firmware=rtl8106e-1_0.0.1 06/29/12 ip=192.168.1.100 latency=0 link=yes multicast=yes port=MII speed=10Mbit/s
       resources: irq:19 ioport:e000(size=256) memory:f7000000-f7000fff memory:f0000000-f0003fff

Output of lspci | grep Network:

06:00.0 Network controller: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter (rev 01)

Output of rfkill list all

0: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no