Go http webserver doesn't support http 3 without external libraries. Nginx doesn't support http 3. Apache doesn't support http 3. node.js doesn't support http 3. Kubernetes ingress doesn't support http 3.
should I go on?
edit: even curl itself - which created the original document linked above - has http 3 just in an experimental build.
nginx do support it.
caddyserver v2 supports HTTP/3 and it's an webserver written in go https://caddyserver.com/features
FYI: There is also an rust webserver which supports HTTP/3. https://v2.ferronweb.org/
It's not experimental when built with ngtcp2, which is what you will get on distros like Debian 13-backports (plain Debian 13 uses OpenSSL-QUIC), Debian 14 and onward, Arch Linux and Gentoo.
Reference: https://curl.se/docs/http3.html