Ooh, I know this one! Here's what I did to get it working and set so it survives a reboot:
In a terminal, run sudo arandr
Set all of the monitors to 1080p
Close arandr
Go to Settings > Display
Rearrange monitors in correct order if necessary
Set the each monitor to the correct resolution and frequency, applying the settings after each update
All monitors should now work, BUT they will not survive a reboot in Pop-OS 22, because the GDM3 login screen will NOT have this information, and will reset everything. So we must copy the pop-os monitors.xml file to the gdm3 config directory:
Thank you! I'm a new user to linux. Went through 4 distros this month until this one, that doesn't seem janky and runs my games at a decent FPS. Having to reconfigure my monitors each reboot was a dealbreaker for me. Your simple instructions worked flawlessly, and i've had 3 reboots without having to change my settings.
I'm not sure if linux is my new forever home yet, but this definitely helps!
Not 100% sure, but I think your desktop environment is usually responsible for maintaining monitor configuration. I don't use pop os, but maybe look for errors saving config to your home directory or something???
Are you on x11? Wayland oftens handles multi-monitor setups more gracefully. If wayland fixes it and you need x11, you would at least know where to start troubleshooting.