Misskey is a federated facebook alternative I heard about on mastodon recently. I’m not too familiar with it myself, but seems worth mentioning.

It has a “groups” feature that might avoid the “instance per person” lemmy workaround you were thinking about. According to this comparison misskey doesn’t have a like button, but a few of its forks do. Not sure about the upload experience; may depend on the app. I didn’t see any clients listed on their site but did a quick search for an iOS app, which exists, so i assume android, too.

Sorry I don’t have more info, but I hope that’s useful. Best of luck! I’ll be looking for a similar solution in the near future.