Giving the author the benefit of the doubt, that's probably how I'd do it. Not hosting the Wii in a datacenter, but set up a VM as a proxy, as to not expose my home internet connection to the world.
You're not going to win an points with the family when they can't stream Disney+ because you had to expose a webserver running on that old Wii to the internet, using your home internet connection.
Couldn't one use cloudflare tunnel to prevent that issue?
I'd assume so, but if you already have a VM running your blog normally, then you can just have nginx/apache/haproxy/varnish/whatever you use forward the traffic, and once you're done point it back to the "real" blog on the same VM once your experiment is done.
He wrote that there's Caddy adding TLS between Wii (which runs lighttpd) and the viewer.
You should read the actual post.
Hetzner is the IPv4 proxy, use the IPv6 address to connect to his network directly.