To give an example on how I think moderation should work. If I follow you and you follow me on some nonexistent platform Y. You see the content I upvote, and I can see the content you upvote. So we'd start with block all by default, with transparency of why something is in one's list.
I pitched a P2P platform like this years ago to NLNet (taking heavy inspiration from I2P's Syndie app, minus the funky UX), though I didn't manage to get any funding due to missing clout as a public developer; to lead such an effort.