DNSSEC doesn't help here. It doesn't run between stub resolvers and recursers like 1.1.1.1.

Probably not, I can't remember the last time I looked at 'resolvectl' output and saw anything other than "DNSSEC: no" on any system so I assume it mostly just doesn't exist in practice

More practically: do you have DoH enabled? If you're using Chrome, the answer is probably yes.