If anyone wants to see another example of an app using Tiptap, I built https://duckbook.ai as a fun/free solo project (it's a Notion-like SQL notebook built on Tiptap, DuckDB, and GPT-4).
I evaluated a bunch of editors (ProseMirror, TipTap, Remirror, Slate, Quill, Draft.js, Lexical) and went with TipTap.
I've been generally happy with it, the APIs/docs are good. ProseMirror is super powerful, but large/slow to work with. Tiptap helped me launch a product much faster, but still pop the hood to the ProseMirror layer in a few places where needed.
Main request is to keep the tiptap/core project free and MIT licensed, even if you raise prices on other pieces (like the managed collaboration server).