I use Cloudflare's DoH DNS (https://1.1.1.1) and tunnel that over Mullvad's VPN.
That way Mullvad can only see the IPs I visit, Cloudflare only see DNS requests coming from the VPN IP, and my ISP sees nothing.
Mullvad's DoH DNS seems nice, but it provides potentially less privacy than the above, so I won't be using it.