A lot of our viewing is done just in stereo, the amp is rarely turned on when using the Humax it is however always used with the AppleTV and Blu-Ray and often with the Firestick.
Disney, prime, AppleTV and I believe Netflix, as I don’t have it, all do programs in Atmos (7.1.4).
ITV will never use Dolby as Dolby considers each region to be a separate channel so wants a fee for each one.
What I do find annoying is having to choose between 4K stereo and HD surround for the same program.