I’ve been looking for something like this that also has a Whiteboard feature (think Miro) to deploy self-hosted at a small business.

It has taken me these places:

Obsidian - has whiteboard, but not collaborative. Sync plugin cannot be self hosted. Open source sync doesn’t have user management.

Affine - ditto. Also not completely open source.

Logseq - ditto. Some text editing features require advanced knowledge of databases to use (ie writing query) making it difficult to deploy to non-technical staff.

Excalidraw - whiteboards only.