I’m also considering just getting a portable, 128GB FLAC player with a minijack connection and moving on with my life without getting involved in networking at all.

Yeah, I’d say that this is definitely the way to go. My .mp3 player only has something like 8 gigs of storage, but it takes a MicroSD card. With a 1 tb card, I can carry all the music I want (and realistically, given that your collection is pretty small, you could get away with a whole lot less than that).

Is it sufficient to set the Enhanced Tracking Protection to “Strict” (which claims to block cross-site cookies in all windows), or is there something else you have to do?

Yes, this exactly! I still cannot fathom how Discord took off. It offers literally no advantages over forums, and introduces some massive disadvantages.