I stopped using adblockers and simply set the entire operating system to use Mullvad's DNS over HTTPS/TLS, specifically the adblock.dns.mullvad.net option. It doesn't have all the other uBlock features, but all ads are blocked in all browsers.
I checked it. I used the adblock.dns.mullvad.net option and adblocking works fine on all browsers without using adblock extensions. The checker on Mullvad's website shows the DNS info as it should.
I think maybe there's no need for Firefox DNSoH settings anymore because the whole OS uses Mullvad DNS now. But I don't know enough about DNS to be sure.
Is this also true about the cloudflare DNS over HTTPS option that Firefox provides in the privacy settings?
If yes, then would it help if I changed the setting from 'Cloudflare' to 'NextDNS'?
Ah damn! I missed that