Right now the XS Max is functioning like a giant XS. No landscape mode on the home screen, and Youtube functions EXACTLY like it does on a spare iPhone SE I use for workouts. Doesn't Youtube function on the Plus models like it does on an iPad?
The YouTube iOS app on Plus phones function the same as their little brothers. The iPad is in its own world of design. That’s up to the developers (google) to fix.
Regarding no landscape homescreen; I suspect it’s because Apple doesn’t want the notch to interfere. It’s very noticeable on landscape.
I agree that the max should function in its own way or more like an iPad. Right now its a xs with a bigger screen. Apple isn't using all that Realestate for anything useful.