good alternatives that do near the same thing?
Headscale turns the $5 VPS into the thing that connects my laptop to my other compute resources while I am out and about.
For example, you can create a token that grants VPN access with inbound SSH as the only allowed traffic. Add that as a secret to GitHub Actions and now you can ad-hoc debug failing CI via `tailscale ssh`.
> no mobile clients
I know of some people however who hacked up their own using the sanctum library (https://github.com/jorisvink/libkyrka)
Definitely a place for both services, IMO.