Interested in these! Any chance you could drop a list of clones?
Compared to Tailscale the main weak point of these clones seems to be ACLs. Tailscale's system is very robust and surprisingly simple. The others I've seen are less well developed. I'm sure they will get there in time, but for now Tailscale is definitely the best if you want to control access.
* NetBird (https://netbird.io/)
* Firezone (https://www.firezone.dev/)
No support for exit nodes for example, or DNS hostnames.