Every time I see tailscale do something really neat I'm always a little disappointed to find out they still offer only the three auth schemes- and I really don't want to tie my networking to google/github/ms. On top of the various tinfoil hat reasons, I know a variety of people who have had these accounts terminated out of the blue, and it throwing out my networking stack would be insanely aggravating.
If you're reading tailscale, I will pay you actual real dollars per month to offer a different not-tied-to-a-megacorp authentication scheme. Till then, guess I've got headscale.