I’ve vaguely thought about this with Split DNS.

My concern would be the need to set up some non-Tailnet mechanism to expose it to the internet and keep it secure. Either port forwarding, Pangolin, or even using Funnel… all of which would be better off on a separate device (and maybe a separate VLAN)

It’d be an interesting idea for sure, perhaps for when I can get myself the separate Headscale-dedicated device