What difference does it make? Even if the DNS queries are completely encrypted, subsequent HTTPS requests made after domain resolution will contain the destination domain (but not the path or request body) in the clear. What makes you assume that ISPs aren't already collecting this information?
The Host header is encrypted when using HTTPS and the SNI is encrypted when using ESNI. In the best scenario (DoH + HTTPS + ESNI), ISPs only get the destination IP, not the destination domain.
That's not so great for a best case scenario, because destination IPs rarely change, and anyone can resolve any domain themselves, making it easy to associate a timestamped IP with a DNS record. I could walk the whole HSTS preload list to find domains.
Quite a few, I guess, but you'd probably be more concerned about how many other domains share the same IP addresses rather than about how many IP addresses this domain resolves to. And the answer seems to be thousands of domains — which in this case doesn't help much as they seem to all be related, but which in other cases might (eg. shared hosting, CDNs…).
