Bookwyrm is open-source, works similarly to Lemmy (i.e. is a federated platform). Storygraph and LibraryThing are also popular alternatives, but IIRC they’re both closed source.

Personally I think just creating a spreadsheet file with your reading data is better. (In LibreOffice, of course.)

StoryGraph is great too.

Android: https://github.com/mateusz-bak/openreads-android

I use Storygraph and have just signed up to Hardcover, which is new but has a good recommendations system: https://play.google.com/store/apps/details?id=hardcover.app