Why don't you support the much more efficient DNSCrypt protocol as well as slow ill-conceived DoH. See: https://dnscrypt.info/
Yep big vote up from me....though I get the feeling NextDNS or its staff don't really pay attention to this forum much at all.
Adguard has this feature should you fancy it.
DNSCrypt never got that successfull. DoT & DoH are the only one. Also DoQ or better ODoH is the future anyway.
Then the future is all some combination of slow, inefficient, unfilerable and/or unblockable.