I wonder if paradoxically federated communication would let you improve the quality of discourse by more proactively banning people. Mastadon works on a federated system where anyone can run they're own "instance" which can then interact with other instances pretty seamlessly. Since people really can leave if they don't like the rules you could be pretty heavy handed with moderation within individual instances to ban obnoxious people or have an invite only system.
PeerTube was a little rougher around the edges, but still very impressive for being pretty new and doing p2p video streaming. There was more lag than YouTube but with decent internet it's fine. The choices for instances aren't great and storage size and bandwith are limited. Storage/bandwith cost money though and that may just be making what's an invisible cost on YouTube visible.
My Mastodon: https://fosstodon.org/@argosopentech
My PeerTube: https://peervideo.club/video-channels/argosopentech/videos