I’m surprised at the negative knee-jerk reaction. I actually love this idea immediately. It encapsulates something I kind of already wanted when using HTTPS Everywhere. This doesn’t guarantee the transport is end-to-end secure; I’m sure plenty will strip the encryption at an LB and then possibly send it back over the internet. But, I think it’s a good addition nevertheless. Here’s to hoping for more DoH and encrypted…
I have mixed feelings about what you wrote. 100% with you that by itself, browser HTTPS-only mode (even by default) is A Good Thing. In isolation, this is a no-brainer and Mozilla's doing the right call. I'm not happy with DoH though, at all. I fall in the crowd who wants to control my own DNS on my own devices (and I do realize that for those less technically knowledgeable, the status quo is putting that in the hand…
You can easily set it up to contact that, but enable some exclusions for specific domains if you wish to fallback to pihole.
It's probably not that efficient anyway to be using pihole's filtering in Firefox compared with just ublock origin anyway.