Brave sync server is open source and self host able.

Everything a browser syncs is syncable passwords, history, bookmarks, cards etc

The “issue” is there is not a user interface element to easily add the self hosted instance url

There are workarounds though

You can read my quick how to here

https://ippocratis.github.io/brave/

Headscale does not support funnels unfortunately

Tailscale is not completely foss.

https://tailscale.com/opensource