So then what do you use or recommend instead?
1 - https://mullvad.net/en/help/dns-over-https-and-dns-over-tls
We are talking a DNS resolver at home or on a VPS.
1. you don't need HA, if it dies you revert back to your ISP DNS while you fix it. And you always have a secondary resolver set up anyway.
2. you just set up its ip address as first dns server on your home router and as DoH on your devices browsers.
2. you don't need to back up a local resolver, the only data it has is cache.
4. a local DNS resolver serving the needs of a household needs very little resource.