YouTube app getting new swipe gesture on Android soon
The new gesture isn't available to everyone, but a limited number of Android users have been invited to test it. If you want to check if you're among the selected few, you can simply open YouTube and see if you can swipe left/right from the home tab.
Since Google has just begun testing the new gesture it will probably take some time until it makes it available to everyone, but such a small improvement won't require too much time.
Meanwhile, Android users have finally got that promised YouTube dark theme that iOS fans received many months ago. If you didn't get it yet, don't worry as these things usually take time, so keep checking your phone.