Firefox

I don't think so, that'd be straight up impossible unless you're behind a VPN. Your ISP can see every connection made between you and any other server, but a VPN uses encrypted payloads between their servers and you, and they make the requests using their servers, and pass the results to you. That way, your ISP only sees that you're using a VPN, but can't see anything else.

As far as I understand it, ECH uses DoH (DNS Over HTTPS) to encrypt the domain name of your connections, but a direct IP address is always required, and most of the times, it's enough to determine the website, as the ISPs can locate just about anything easily. However, the ISP won't be able to (easily) know anything else about the connection, which remains unbroken between you and the server you're connecting with.

But still a very good feature nonetheless.