I use 2 external monitors, one over DisplayPort and second one (amplifier with projector) occasionally over HDMI. The external monitor works fine, it is enabled by default when I reboot, but when I connect or turn on amplifier with projector, although detected correctly, it is not enabled (it is the same if I leave it connected and just turn it on or if I physically re-plug the HDMI cable). I can enable it manually in Display Configuration in system settings (KDE) but it is annoying to do this manually all the time. It used to work with Manjaro automatically for years without problems.
There is also another difference: even if I enable the amplifier/projector manually the screen behavior on my external PC monitor over DisplayPort gets weird - all windows, when maximized, are maximized only to 2/3 of available display height, so obviously to the smaller vertical resolution of the HD projector although the UD monitor is set to primary. Though, I can resize them manually to all available height. The taskbar below is rendered correctly, at the bottom of the screen.
I’ve already tried to downgrade and upgrade kernel, it did not help. I use Linux 6.1 kernel at the moment with latest updates.
My graphics card: NVIDIA GeForce GTX 1650 (hybrid)