Not to mention this is an attack on multiple fronts: do you _really_ believe DoH is about privacy?
If you live in the U.S. for most major ISP users it's probably a wash and you're just letting a different party have your info. If you live in a nation that desires to control what you consume online then it probably is a net gain.
That makes me think of the reason Tor has Entry Guards where the first hop is limited to just a few selected nodes instead of random: https://support.torproject.org/about/entry-guards/