Did a fresh install of linux mint recently, because of that a good chunk of my software has been FOSS, however, when it comes to all the gaming related stuff I've installed (drivers, clients, etc.) its been a hit or miss with more proprietary software then i'd like.
Will say, I've struggled for a while to find a good open source music player for local files, I'd love some recommendations (currently trying Rhythmbox but I don't feel I'll love it)
Try Strawberry, Audacious, and Lollypop. There's a lot of options, it just depends on what you're looking for. I could give better suggestions if I knew what features are important to you.
I don't know if I've used Strawberry, but I used Clementine, from which it was forked for several years. Like OP, Rhythmbox wasn't doing it for me. Clementine/Strawberry is definitely worth a look.