I think you have some reading to do.
Nowhere do “people just run a local resolver”. Grandma and aunty Beryl certainly don’t, nor does any other ordinary person. If you want secure DNS you have to build it in to the browser.
Only systems people think that this is the sort of thing that ordinary people do.
If Grandma has a grandchild that knows how to set up a PiHole, it's a different story. But that's certainly not the majority of Grandmas or the majority of wifi routers.
How many people do you know that running local resolvers? How would this even work on Windows?
The world doesn’t need another encrypted dns solution that only works on Linux