After running #retroarch on my S22 for a week I can say that I am overall happy with the results:
NES ✅️
SNES ✅️
GB/GBC/GBA ✅️
PSX ✅️
PSP: not so great, even after installing the recommended files. I think there is some tweaking necessary in order to get it working properly.
I decided to just break out into #PPSSPP and it just worked without further tweaks.

For PS2 (mostly 60FPS with some dips on NFS) I'm using #aethersx2. I am yet to test more demanding games.
It did get 🔥 though.