I created a video on my desktop and uploaded it to YouTube. Because I made the video less than 40 seconds long and purposefully used a vertical 1080 x 1920 aspect ratio, YouTube assumed I wanted it to be a YouTube short. That was great for me but a side effect is that YouTube refused to allow me to pick the thumbnail.
YouTube automatically picked a "hideous" thumbnail for the video and I can't change it. When I try to change the video via YouTube Desktop, I see this error:
"You can change the thumbnail on the YouTube mobile app"
When I internet search the error, I am directed to various support pages by Google that hint I should use the YouTube Studio app for Android. When I use the YouTube Studio app for Android and edit the video, there still is no way to change the thumbnail.
How can I change the thumbnail for my YouTube short if both YouTube desktop and YouTube studio app have apparently removed the edit thumbnail function?