There is a method of reorganising your playlists put it's not in alphabetical or anything. You have to manually do it. If you'd like to find out how to MANUALLY reorganise your playlists, follow the steps below.(This is assuming you're on desktop. For options on mobile/tablet, look for the link at the bottom of this post and open it.)
Playlists in Your Library
To reorder your list of playlists in the menu on the left, just click and hold a playlist title to move it up or down.
You can also organize your playlists into folders:
Right-click a playlist in the menu on the left of the desktop app.
Give it a name and press enter.
Drag playlists to a folder. You can even create folders within folders.
:This works forSongsinYour Librarytoo!
Click the column you want to sort by, for example:
Alphabetically, byTITLE,ARTIST, orALBUM.
By most recently added, with the calendar symbol
By song duration, with the clock symbol
Note:Adjust the app's screen size to reveal more columns.
Click the column again to reverse the order, click again to go back to the original order.
For more info like how to do this on mobile/tablet, check this article out! (Which is also where I got this info from)