DoH isn't to be avoided at all costs because you're handing over all of your requests to a third party (which you end up doing anyways regardless of if you use DoH or not). The real threat is that companies like Firefox are attempting to take control over which portions of the internet you are allowed access to. When your browser is choosing your DNS provider they can now effectively remove websites from the internet without having to interfere with their web hosting, or registrar. They simply block DNS requests to your website and now no one running their implementation of DoH (Which I think was through CloudFlare(!) the last time I looked) can access your site and they've effectively removed you from the internet. If you have a DNS provider that you trust, and that you set yourself than DoH is fine and dandy, but that's now how 99% of humanity will end up using it.