Headscale is pretty light on resources, especially since it doesn’t come with a webui (there is third-party ones like headplane you can use though). RAM usage is like 70mb for me currently.

If you want to have more control about it and become independent of the SaaS offering, you can even selfhost headscale, a FOSS tailscale control server. I run it myself with zero issues.

Maybe Tailscale could be super useful for this!