#Headscale - iDevice clients report hostname as localhost (Apple privacy - go figure) so to have a distinctive hostname you have to change the Device Name in tailscale client. If you didn't do that before registering the device you need to delete the node from headscale and reauthenticate it (and change your local DNS records for your homelab, if needed because the node will get a new tailscale IP).
No idea if you can do this by fiddling with headscale db.
