AirPlay from iPhone for iTunes content

[MrQwerty111]

Looking for a new TV, first 4K one. I’m down to a Sony and LG for few reasons, one being support for Dolby HDR. 

So Sony/Apple announced In Nov/Dec 2019 that Apple TV+ app would be coming, it still hasn’t but AirPlay is supported on recent TV’s now. 

So if you AirPlay from an iPhone to a Sony TV, for an iTunes 4K Dolby HDR movie what resolution etc does it do it in?

I believe the Apple TV+ app on other TV’s do iTunes in 4K and Dolby HDR, but what about AirPlay?

Is Disney+ app on the TV’s now as well? 

thanks

[Tonycv51]

To be fair to Sony they won't always know. I recently tried to get an answer from Google on why built in chromecast doesn't work in 4k. It could be the chromecast library, something inherent in the sony tv, or the 3rd party app you're casting and how it's servers react.