>I wonder if Headscale can also use internal credentials? As far as I remember with tailscale you had to log in with Google or Microsoft which is another total deal-breaker. But I haven't looked at it in ages as the hosted variety was a non starter anyway.
from the project page:
https://github.com/juanfont/headscale
>Node registration
> • Single-Sign-On (via Open ID Connect)
> • Pre authenticated key