2a/ ok, I misread what was the intention, maybe it's a good idea then
3/ it's not about "better maintained", it's about trusting the internet on sensitive data, which you should never do, because dns is easily spoofed and nginx resolver was not written to operate in a hostile environment. if you don't have a local caching resolver on your machine (which you should), even trusting your cloud provider dns is better than trusting goog one. nginx documentation even says " To prevent DNS spoofing, it is recommended configuring DNS servers in a properly secured trusted local network. " on http://nginx.org/r/resolver
3/ it's not about "better maintained", it's about trusting the internet on sensitive data, which you should never do, because dns is easily spoofed and nginx resolver was not written to operate in a hostile environment. if you don't have a local caching resolver on your machine (which you should), even trusting your cloud provider dns is better than trusting goog one. nginx documentation even says " To prevent DNS spoofing, it is recommended configuring DNS servers in a properly secured trusted local network. " on http://nginx.org/r/resolver