DNS over HTTPS. It is a new(ish) way to do lookups that deals with the insecurity of most DNS setups (where packets are often neither signed nor encrypted) by hitting a resolver over https. Often the application will hard code the resolvers it intends on using, which leads people to believe it is adtech as it allows apps to bypass blocking by PiHole and the like. It, like most tech, can be used or abused.
Once the system, or network admin would set the DNS servers up and everything on the system would use those. There is no reason why that paradigm couldn’t continue and move to DoH.
The other change is that applications are now bypassing the system-configured DNS and sending requests (and thus data about what you are looking at,) where the application wants. The “centralisation” issue also comes into this. But again, the change from a system-level to per-app setting could happen with regular old plaintext DNS.
DoH is part of the discussion in both cases, which clouds the debate.
