Shortcuts

Action	Keyboard Shortcut	Controller Combination
Open Menu / Back	F1	Select + X (or Y)
Save State	F2	Select + R1 (Right Bumper)
Load State	F4	Select + L1 (Left Bumper)
Fast Forward	Hold Space	Hold Select + R2 (Right Trigger)
Toggle Fast Forward	Space	Hold Select + R2
Exit Emulator	Escape (or Alt + F4)	Select + Start
Rewind	Hold R	Hold Select + L2
Reset Game	H	Select + Down
Take Screenshot	F8	Select + Up
Pause / Unpause	P
Volume Up / Down	+ / -
Toggle Fullscreen	F
Mute Audio	F9
Save/Load Slot Change	F7 (Next), F6 (Previous)
Shader Cycling	M (Next), N (Previous)

Random

No pause when losing focus

settings > user interface > set "pause content when not active" to off

Saves

Flatpak

$HOME/.var/app/org.libretro.RetroArch/config/retroarch/saves/Beetle PSX HW