Can you recommend some p2p technologies that people can start building with today?

Eg I’m tempted to go with a stack of a centralized Postgres with a SQLite for each user (a la Electricsql, mvsql, etc.) because I want users to have their data local as much as possible (in their own SQLite db) but a centralized Postgres database still feels logistically necessary to coordinate eg user accounts and sharing.

I’m all ears on better p2p solutions. I’ve looked into things like eg using matrix or nostr but they don’t feel like the solution I’m looking for yet. But I’m eager to find something that can keep data local and have sharing done more p2p.