When I used to manually connect to my ISP everytime I wanted to surf, I did not have any DNS related issue. This was apparently because I used to stay connected for short durations of time (say, 6 hours.)
However, when I kept my Dataone connected for long hours using my Router, I faced major issues. The DNS failed to respond. The issue was not (only) latency, but also “uptime” and reliability. At certain times, some of the automatically assigned DNS tends to have high latency and also after long period of connection, the DNS tends to fail totally.