Advice on editor collaborative solutions

I just wanted to ask the community for advice and/or suggestions for the smartest method to turn my editor from stand-alone on a local computer to cloud-based multi-user collaborative. My implementation is pure Prose Mirror and vanilla JS, as such I do not use commercial solutions like TipTap where they have a solution they built for their paid service.

Are there other open source or even commercial collaborative add-ons for PM that are out there, so I would not have to reinvent the wheel for this use case?

Hocuspocus (js server based on Y.js) is easy to setup with a pure Prose Mirror editor. Server side, you’ll just need a way to route the requests to the hocuspocus websocket server port. Client-side, you’ll need a few easy adaptations (like replace the history plugin), and a few maybe-not-so easy ones, depending on the format of your document (hocuspocus/yjs has its own document format) and the way you load/save them.