Welcome to the 4K HDR party, Android users.
The YouTube app that’s available on Android devices now officially supports streaming video at a 4K resolution with HDR. It’s overkill of course, as most smartphones at this point don’t have 4K displays (and it’s of questionable benefit to those that do). But it’s an option now.
The feature appears to have gone live sometime in early- or mid-February, according to
Note that you can do this even if your phone’s display tops out at a lower resolution. I’m on a Pixel 3a XL myself and had no problem selecting 2160p on videos that support it in the YouTube app. Changing that setting just won’t amount to much if your phone doesn’t have a 4K display.