I mentioned it back
here but you didn't reference it specifically.
So I'll mention it again, AFAIAA iTunes, (not Apple Music - the streaming service), allows you to purchase albums/individual tracks that you can download and are DRM free - downside being you have to use ITunes software (or whatever they call it now) on your PC to purchase/download like Amazon.
Some internet search results, some you may already know about but doesn't hurt to mention them.
Jamendo - Independent artists - Generally free streaming, free download (MP3), purchase a licence for commercial use (HQ audio file).
Bleep - Independent artists - Physical and digital music for purchase (320kbps MP3 | 16bit LL WAV/FLAC).
CDBaby - Independent artists - Digital music for purchase (all 320kbps MP3).
Other sources that are DRM free:
Games (
Steam,
GOG, etc) - I have a few games that included OST albums as part of the game or DLCs, (eg. S.T.A.L.K.E.R: Shadow of Chernobyl).
Bundle sites (
Humble Bundle,
Groupees, etc) - I've purchased bundles of a variety of different music genres whether they were something I was interested in or part of a humanitarian type deal, (eg.
2017 Mexican earthquake,
Cryo Chamber bundle).
Archive.org -
Music (mixed bag, browse the categories),
Concerts.
FreeMusicArchive - Free and Royalty Free music, recently acquired by
Tribe of Noise.
FreeGal - Offered by some library services, (here in Australia at least), allows MP3 downloads and transfer to other devices, also streaming apps for your phone, (
Android,
iOS). Essentially free as long as you have library membership.
NOTE: The only ones I've used are Steam, GOG, Groupees, and Archive.org - no personal endorsement of any of them ... but I have just noticed a couple more bundles on Groupees that look interesting ... oh well, down goes the PayPal balance ...