Please correct me if I am mistaken, but unless there’s a local resolver for every single one of your clients, aren’t the DNS requests sent in plaintext to the upstream of your local resolver?

That might not be an issue for your situation, but I recall the benefit of something like Quad9’s offering is the encryption between client and their endpoint(s), particularly for untrusted ISP or similar.

> I prefer to run my own local recursive resolver.

Used to be fine. I stopped doing it when average TTL dropped to 300 seconds and it takes far too long for my local recursor to get the answer >100ms, when 3rd party resolver delivers in <10ms.