And there’s no good way to stop that.As long as they rely on your own network for their external connectivity, you can always firewall them (at the expense of any connected features you do want to use, perhaps, but then I suspect most of us would agree that 99% of those are junk in most smart TVs anyway and be OK with that limitation).
The problem comes when they can form their own connections, but in that case they're not under your control anyway, DoH or not.
