Plus a centralized identity provider, which is a plus or minus depending on your threat model, https://tailscale.com/kb/1013/sso-providers

Introducing obscurity to the process doesn't make it insecure. Criticism of "security through obscurity" is that security shouldn't rely on obscurity. The system should remain secure even if the attacker knows every detail of your system. Here the point of the "obscurity" (if you can call it that) is to avoid blowing up your logs and wasting compute cycles and energy on attempts that will fail anyway.