Whilst looking for a way to access kodi when out of my home network, I stumbled upon this thread.
I think my solution will only work if you, like me, have a seperate Pi/server running besides the kodi server/SBC/etc.
When installing tailscale on my seperate Pi, I connect to it via Tailscale apps.
Then, using subnets https://tailscale.com/kb/1019/subnets, I'm able to access my kodi player and stream from there.
Maybe not your use case but wanted to share for any future searchers stumbling across this forum post.