AimIsADickISP DNS servers are the defaults and are commonly used. Unfortunately they often aren't as reliable as non-ISP DNSes servers and often track what sites you visit! e.g Cloudflare or Google DNS servers are a lot more reliable than Comcast or AT&T's DNS servers, and the former (supposedly) doesn't track you.
this guy watched a linus tech tips video on DNS and applied it to game network performance im dead