@jay @andypiper @HauntedOwlbear ListenBrainz is the active FOSS alternative:
https://listenbrainz.org/

Libre.fm was another last.fm alternative, but it seems to have gone dormant in 2022 while they try to rewrite the software from scratch (someone should update Wikipedia):
https://en.wikipedia.org/wiki/Libre.fm
https://github.com/foocorp/gnu-fm
https://github.com/foocorp/hacienda