also, i checked - nobody has done this already. someone made a more complicated thing that handles NIP-57 as well for something: https://github.com/AreaLayer/LNURL but i just wanted something simple.
my VPS is cheap, 3.8 euro a month, and the domain registration for my first year was literally 1 euro, and it's more than adequate bandwidth to run a wireguard VPN tunnel, and using my domain, host my NIP-05 and have a shiny domain name thing. lol.
so, i'll put together a simple go app that just pulls an LE cert, and serves up the proper NIP-05 JSON verification file et voila.
maybe something more will spring to mind as a use for it but for now this isn't a terrible waste of 6 euros now and 4 a month to have a vpn and bulletproof impersonation proofed nostr identity.