In general it seems like moderating platforms with millions/billions of users is a fool's errand, but is required to be attempted due to the level of centralization we've ended up with. Regardless of how much of it is automated away via blackbox ML algorithms lacking transparency or via outsourcing to cheap labor that spends their days looking at terribly offensive and shocking content, the end result is going to hav…
Of course you could create huge echo chambers that way, but that happens anyways when you curated your followers, so I don't see that as a huge issue. Just now in addition to deciding who you follow, you also decide who you block.
Twitter (or whatever platform) would still be responsible for eliminating bad actors (spammers, people posting illegal content) but other than that could just let users curate what they see on the platform.