Facebook group like platform for self hosting

Hi,

By lack of an alternative, I wanted to start a Facebook group to stay in contact with some people, share posts and pictures, like and comment on those etc...

However, several people have indicated to no longer support Facebook (which I am happy to hear to be honest).

Are there any easy to use and host alternatives? Preferably with a ready to use Docker compose file.

Thanks.

Edit: some more details: I want a platform where I as admin can create a user account (no public registration possible). That user can then create a group (in my case I want to stay in contact with the owners of the brothers and sisters of my new puppy).

The user (group admin) can invite others to the group (who then can create an account for that group only).

Only public posts on one shared group timeline. No direct messaging or other fancy features needed.

Edit 2: this platform would have only a handful of users and should be completely standalone. I'm not looking for a social media platform.

If this works well I might create a few other groups for e.g. family or other hobbies. At most it would be 100 people or so in a group with fairly low traffic.

I really only needs to do one thing and that's share a public timeline where anyone can post.