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

Try the literature board on 4chan especially some of the resources in the pinned posts at the top for some good recommendations. Not exactly like Goodreads but some good reading ideas from the community.