What sort of keyboard and mouse are you using? (USB, wireless, bluetooth etc)
I use Fedora 32 on a PS4 pro for emulators, but Retroarch for Catjaro does up to PS1 well. Dreamcast pushes it and you can run Reicast on Manjaro but I've never tested it for performance.
For PS4 Linux, Reicast gives better performance most of the time but Retroarch has some other games not supported by Reicast. As a piece of advice, some popular Dreamcast games (Marvel vs Capcom 2, Capcom vs Snk 2, Crazy Taxi) have PS2 releases which run in Orbis really well when converted to a PKG. Some also have arcade releases which run much better in things like MAME (Mars Matrix and basically any other shmup, Garou and any other 2D fighter not already listed) and you are better off finding other methods. Things like 3rd Strike have native PS4 releases things like Anniversary Collection.
Gamecube and Wii aren't great either but I'm not sure of the specifics because I've never tested them. (I just use a Wii and a Gamecube controller for those)