i am 95% certain i run unbound in a datacenter, and i have pihole local, my PC connects to pihole first, and if that's down, it connects to my DC; pihole connects to the DC and one of the filtered DNS providers (don't remember which) and GTEi's old server, that still works and has never let me down. No, not that one, the other one.

i have musknet, though, so i can't edit the DNS providers on the router without buying another router, so cellphones aren't automatically on this plan, nor are VMs and the like.