Also: it is part of the architecture of DNSSEC for clients not to do full validation, which requires that they act as their own recursive resolvers and eliminates shared caches.
Obviously, in the early days of DNSSEC there were more improperly signed zones. But since Google's public resolvers do DNSSEC validation, that is mostly a thing of the past.
Then there might be the rare case of middle boxes breaking DNSSEC, but as far as I can tell, that is extremely rare.
There is no connection between DNSSEC validation and being a full recursive resolver. You can easily have a stub resolver that does DNSSEC validation. Or, if it is easier, have a local validation recursive resolver that forwards to another recursive resolver.
In short, 'Just google it' often means that somebody doesn't actually have the relevant references.
For privacy reasons, DNS over TLS and DNS over HTTPS are still a good idea. So even with DNSSEC you would need one of those.