We have a publicly available rule that you can subscribe to for blocking access to most popular DoH services.
Subscribe to it from your adam:ONE® dashboard by accessing the SUBSCRIBE LINK.
This rule uses the NXDOMAIN method vs the Block method that is used by standard block rules - which is what you want for DoH.
NOTE: If you are an MSS adam:ONE® client (Managed Services) you are already subscribed to a rule that will achieve this and you do not need to subscribe to the public available rule.