Yeah, we use yjs and a fork of y-sweet [0]. We have a custom-built control plane that allows us to support many different types of relay server configurations (including self hosting, multi-tenant, per-relay, per-document) and optimize for cost.
Your project looks cool -- especially sub-document support -- thanks for sharing
I’m building a Y.js sync server: https://github.com/nperez0111/teleportal