NB. I don't use Windows and I don't use "Private DNS". I'm referring to using HTTP/1.1 pipelining^1 with a TCP client plus TLS forward proxy or HTTP/2 with an ldns-based client to fetch DNS data in bulk, outside the browser, from the command line. I got some incredible speeds from Mullvad
1. Not every service still supports 1.1, RFC recommends H2
I've found DoH was pretty unusable for me on Windows because the TCP connection doesn't seem to stay open between queries. No idea if it's a software or network issue, but big unpredictable delays on DNS queries broke all kinds of weird unexpected stuff.
I stopped using Mullvad when they discontinued OpenVPN support (another one to add to the parent list). OpenVPN, if nothing else, provides a wider array of connection options that have a better chance of fulfilling your specific network needs. It supports both UDP and TCP, unlike WireGuard.
I say this respectfully, but Mullvad is perhaps “dumbing down” their VPN service in an effort to simplify their operations and cater to a wider and more general audience.
I'm not the person you are responding to, but Proton VPN? That's what I switched to after it turned out one of the two Mullvad founders took my money and gave it to a local lunatic politician.
I did too, but I really miss Mullvad's static port forwarding system. It's a pain having to continually run a NAT-PMP client, and it doesn't work when you're connecting to ProtonVPN on your router.