I own quite a lot of mp3s legally. Host them on a 50 dollar raspberry pi with something called Navidrome which uses a protocol called subsonic.
I can stream my own music from my home to my phone etc or anywhere. Otherwise yeah just having them locally is the other best option.
I’ve played maybe an hour or 2 on my PS2 maybe a year or two ago and the mechanics sounded so amazing, but in execution they don’t seem to work as intended like you said.