Your ISP should have a DNS revolver closer to you. "Should" doesn't necessarily mean faster, however.

I’ve had ISPs with a DNS server (configured via DHCP) farther away than 1.1.1.1 and 8.8.8.8.

In case of Denmark, ISP DNS also means censored. Of course it started with CP, as it always does, then expanded to copyrights, pharmaceuticals, gambling and "terrorism". Except for the occasional Linux ISO, I don't partake in any of these topics, but I'm opposed to any kind of censorship on principle. And naturally, this doesn't stop anyone, but politicians get to stand in front of television cameras and say they're protecting children and stopping terrorists.

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Not just that. ISPs are often subject to certain data retention laws. For Denmark (And other EU countries) that maybe 6 months to 2 years. And considering close ties with "9 eyes" means America potentially has access to my information anyway.

Judging by Cloudflare's privacy policy, they hold less personally identifiable information than my ISP while offering EDNS and low latencies? Win, win, win.

No, your ISP can have a server closer before any external one.