PSA that if you have a ham radio licence, anywhere in the world, there are IPv4 addresses available for you for the taking at ARDC (AMPR)[1].
You can either get a block of /24 to announce yourself (you've got to cover all the technical setup and costs of this) or use their free 44net.connect service and just organise a wireguard tunnel.
You cannot use it for anything commercial.
I have looked into acquiring an ipv4 block many times but never came across this. Thanks for the lead!