I’m firefox everwhere because I have to use a PC at work, and well, even though it has problems I like how I can customize it. Reading a blog post about their Enable DNS over HTTPS feature I explored NextDNS.
I’ve now installed it on all my devices and at the network level. All my DNS traffic is going through them and it’s fascinating.
The web is faster (due to all the blocked trackers and ads), and I can see what is trying to load where. I’ve used the whitelist to make things work that get broken. If you know of Pi-hole - it’s like that but running at the router level.
Why would you believe it might be a massive mistake? I think that DoH is a great idea. But regardless, if you have a problem you can just back it out. Seems like a worthwhile experiment, at worst.
Note that there are other ways to block trackers and ads (such as web browser preferences, extensions, and/or a host-based application firewall such as Little Snitch), so if you were to use a service like this only to block trackers and ads (which seems not to be @philstollery’s only intention) then you might have made a mistake if other options were better suited to your requirements.