My bad, I just read through the wiki and when using lr-pcsx-rearmed it doesn't matter if it's upper or lower case.

You can also try a fresh Retropie image and see if your games work. If not, then there is something wrong with either the bios or the game.

When i update retropie from 4.0.1 to 4.0.3 (or 4 i don't remember) i got a lot of problems. Controls stopped working insidee psx games, and the bios wasn't been detected! I put the bios in the psx roms folder and it works.... But I don't get why they launch update that breaks user configuration completely