Tailscale seems a bit too centralized. And can't sign up with email? Have to use a big tech SSO? Hmmm.
Discussion
If you want to roll your own, then Wireguard is what to use. Tailscale is built using it.
This is a very handy guide for setting it up:
https://www.digitalocean.com/community/tutorials/how-to-set-up-wireguard-on-ubuntu-20-04