Hurmmm.
I have actually made a custom OS for dealing with troubleshooting exact problems like this.
It’s made to be extremely friendly towards beginners who just want to have a device to play games, and not have to mess around with anything.
It’s based on the latest official release as of the 3rd of September 2020 last year. I don’t think there have been many huge game changing updates since then. If anything, mine should theoretically be more up to date, eg, Retroarch is on version 1.9.0 which is the current official stable version.
Higher versions for emulators (eg snes) usually relate to being more accurate, but in turn end up running slower. With desktop computers getting ridiculously powerful, running slow is not a problem, but we’re dealing with a much lesser powered unit here.
The bios is in a fixed location, however the PlayStation bios isn’t stored in the same location as the rest of the bios. Check my thread above, and look at the setup section. It tells you where the Bios are stored for different consoles.
The freezing problems you have mentioned were things I experienced in the past with a stock OS. I don’t experience them with my customised OS.
I also haven’t ever experienced file system corruption. This was something I uses to get on previous OS’s, but that was possibly addressed in the official 0.5 OS too.
Basically, if you have a spare SD card, give my OS a shot. It was made to solve everyone’s problems without actually having to spend time troubleshooting.
If we did go down the path of trying to get your current OS stable, I fear it will be way too hard to do without me physically holding your unit. Even if you have millions of Roms, or special customisation, you’re better off starting on a firm foundation that is workable. Just watch out for potential screen flickering issues. The most recent post I responded with addresses it. Otherwise just search for “flickering” in the forum search bar.