Is it based on ActivityPub? I don’t really know much about it other than Jack Dorsey is involved.

I’ve been using AntennaPod and it is no frills and works flawlessly.

Then stand up your own server and govern it as you please.

no, you’re wrong. This organization is basically still experimenting, and they have come a long way over the years. There are also efforts to trap plastics at mouths of rivers to try and slow down polluting the ocean. There is hope yet.