So this is somewhat similar to Iroh?

https://github.com/n0-computer/iroh

I'm a big fan of iroh, but I think iroh's holepunching algorithm is at least partly based on tailscale's, so it's not 100% accurate to say iroh got there first. (Just the "as a library without a control plane" bit.)

In particular:

https://github.com/n0-computer/dumbpipe

https://github.com/cablehead/pai-sho

https://github.com/n0-computer/pigeons offers the same but with SSH. I use it in my homelab extensivelly for access, tunneling smb, postgres and some other minor bits.