[com]

Consider something like Mobilizon[0] - it's ActivityPub based, like Mastodon, but apart from the federation capability, might have the feature set you're looking for?

[0] https://joinmobilizon.org/en/

[aloisdg]

Cam here to talk about mobilizon. The project is quite easy to work on and it is made in Elixir. :)