the folder structure is a bit different for rgb-pi for arcade games. fbneo, mame need to be under a folder called arcade. I also created a tool to migrate os4 to pi5 and add more cores
https://github.com/forkymcforkface/RGUI-Pi
https://github.com/forkymcforkface/RGBPi-Extra
It sounds like you may have funked up some setting. I would suggest going to settings>system>system restore (pw:1234) this will put all settings back to default.