Google is working to optimize the YouTube experience for larger screen proportions, and the app is now optimized for portrait mode, so if you want to rotate to landscape mode, you'll find that landscape mode is basically portrait mode, but with a rotation
But with the current experience, channel updates appear in the top row while the subscription feed is below it, the current look is a bit crowded, while there is some wasted white space horizontally
With YouTube v19.50.36, Google is testing some useful UI changes for landscape mode. The change has been spotted on a foldable phone , but it should also be available for tablets when it launches
The new design improves the subscription feed layout, while channel updates appear on the left navigation bar, and videos appear in the second column
The thumbnail size has also been fixed to take advantage of wasted white space and make the UI easier to navigate, and the channel display is now clearer
Thanks to the changes, you have more information on the screen in landscape orientation and it generally looks better and clearer. At the moment, this new design is being tested, so it has not been officially released and we do not have details on when it will be released