Hi, welcome to the forum, currently there is no way to sort playlists, you have to shuffle them around manually. I’m used to this as it’s been standard across most software for years, so I did an initial sort on first load then all I do is manually move any new ones into place as I create them.
It’s best to do it on the desktop app as you can use your mouse to drag the playlists around. If you want to scroll it up the list you can grad it up so far and the playlist list will start moving in that direction.