ECH is supposed to be used alongside DoH.

https://blog.mozilla.org/en/products/firefox/encrypted-hello/

It’s also important to understand that no one technology can be a panacea. ECH works alongside other security and privacy features in Firefox, including DNS-over-HTTPS (DoH). DoH encrypts DNS queries to protect the translation of website names to IP addresses, which ensures that website names aren’t visible to the network in DNS traffic and is essential for ECH to be effective.

DoH alone should prevent DNS blockages, ECH would also prevent packet inspection revealing the domain.