I would not be surprised if Google TV devices will sooner than later start using DoH to 8.8.8.8

I'm a noob at this, but can you do that when it is DoT or DoH? Like I thought the point of them is that you can't forget the DNS request. Even harder with oDoH, right? So does that really get around them?

yea when it's DoH or DoT I don't think you can re-route the DNS request inflight. (where the device thinks it's talking to 8.8.8.8 but it's not).

You can block access to other resolvers though which usually works.

Eventually devices might just start using hardcoded IPs...

I've explored that! Couldn't figure it out but it certainly sounds possible. And even easier solution is just to block all DNS resolvers except your chosen one. When 8.8.8.8 doesn't work GDevices will fallback to the DHCP assigned resolver (usually your gateway)

My router owns the IP 8.8.8.8 when seen from inside my network; the Roku literally can't ask Google for DNS via DNS, HTTP, or DNS-over-TLS.. It also answers DNS requests on port 53, and believes that there is no scribe.logs.roku.com, along with many other domains.

The downside is that Google seems to think I'm in a botnet, and wants us to login to see anything on YouTube.