For a decentralized social network to be viable/sustainable (especially on the scale of something like Twitter), it has to be truly P2P, not federated on volunteer-run servers paid for through donations. That volunteer-run federated model is really only sustainable for smaller niche communities, not a global social network.
As of right now, the closest framework I can think of to handle something like this is a social network built on OrbitDB: https://github.com/orbitdb