I don't like DoH either. However, you seem to be inadvertently advertising one of its benefits. Even if you do not use your ISPs DNS servers, DNS is not encrypted so your ISP can record all of your queries anyway. DoH set to the server of your choice stops your ISP from seeing all of the queries. I completely agree that there should be one resolver for the system or subnet/managed network. If that one resolver uses DoH, fine, but do not give individual applications the power to change unless it is a specialized application. Certainly do not use DoH for a general purpose web browser. I think Microsoft is going in the right direction of enabling DoH at the Windows system level and allowing the user (or admin) to configure it if they choose to use it.
At least Mozilla is making it optional. I would stop using Firefox if it became mandatory (more likely, I'd just configure my firewall to block it).