It's possible. Applications don't have to rely on the OS provided mechanisms to lookup names, or even rely on DNS to get an IP for something.
Chromium contains its own DNS resolver so connects directly to a DNS server rather than use the OS, but it would normally default to your OS settings (and only use DoH when they find a matching entry in their list of DoH providers).
Desktop Firefox is an example of an app that defaults to DoH from 1.1.1.1 (in some places).
Chromium contains its own DNS resolver so connects directly to a DNS server rather than use the OS, but it would normally default to your OS settings (and only use DoH when they find a matching entry in their list of DoH providers).
Desktop Firefox is an example of an app that defaults to DoH from 1.1.1.1 (in some places).