Just do the cheap unlimited personal plan and hook up a shit load of external HDDs to your PC. I have a system where my NAS syncs to my PC which syncs to Backblaze so I can sorta hack my way into unlimited NAS backup for $10/mo.
3-2-1 backup where the primary source of data is the NAS, on site backup is desktop PC external HDDs, off site backup is Backblaze.
Some consider it a hassle, others of us obsessively enjoy manually downloading and sorting our files into our folder structure.
I’ve got a collection going back to a 128k MP3 from a Napster download in 2000. Hundreds of gigabytes of lossless music.
Bandcamp is great, but I use Redacted for those I can’t easily find.