NextDNS works because it uses several public lists, but it’s kind of abandoned and HaGeZi removed it from his recommended DNS services because of the complete lack of customer support. The guys from NextDNS moved to dns0.eu. You can set Mullvad’s own DNS service in the browser, and being an ecosystem specialized in privacy, a much bigger company, and having curated lists instead of just shoving tons of public lists without checking for duplicates (NextDNS), correct me if I’m wrong, but I think Mullvad’s DNS probably offers a more concise service.