[zahllos]

While I agree that Mozilla's by default decision is wrong, this is not actually true of other browsers. Chrome will check your existing DNS provider to see if they support DoH and if they do, query that way. If not DNS proceeds as normal. Microsoft are adding the ability to use DoH in windows, but they won't change your DNS settings, so you'll need to configure it. So other than Firefox there's no "use DoH by default" anywhere.

Firefox's choice isn't the best but you can disable it. Set network.trr.mode to 5 in about: config, which means disabled and deliberately configured as such. Then Firefox won't ever try to use DoH.

As others have pointed out, you can also use other resolvers than cloudflare's, through network.trr options.