at least none of the major websites on the internet do.
To get ECH to work for me I had to enable DoH in my local Unbound DNS daemon and point Firefox to it rather than using unencrypted DNS on my LAN. I had to force a refresh (shift-F5 on tls-ech.dev). I only use my own recursive DNS so I get query logs and can block some ad/malware sites.
[1] - https://crypto.cloudflare.com/cdn-cgi/trace
[2] - https://tls-ech.dev/