tptacek parent
You're not going to get either of those things. The market has converged on DoH and applications will continue to run it, and you're not going to get a law giving you root on all the devices that go on your network. If you're concerned about Chromecast's DNS, don't hook up a Chromecast. I don't, and I'm doing fine.
Saying "the market" when you're mainly just talking about Firefox and Chrome implies that it couldn't be changed just by convincing a small set of specific people.
And we'll yet see about that law. Right to repair is pretty popular.
Good luck. It doesn't bear in any way on DoH, though.