Yes, changing the SD setting has been mentioned a few times along with that it does not appear to change the playback resolution (fixed it for me a while back). However, someone still needs to address the root cause. Now that we have shown what fixes it, it should be easy for them to figure out what that setting is "actually" doing in the code.
Funny. Apple says to contact the app in which you are trying to stream AppleTV through.
I’ve only had Apple TV+ for about a month and this issue is putting me off watching it. I managed to get 6 months of Apple TV+ for free through my PS5, but prefer watching through my Roku express. If they don’t sort out this issue with Roku devices then I’ll be cancelling my sub before my first payment.
BTW, I’ve tried EVERYTHING suggested in this thread!