The other day I shared a link out where you could request to do your transfer from Google Play Music.
Well, maybe it worked as today I have the opportunity to do so.
I had to go directly to the URL: https://music.youtube.com/transfer to see the above screen, but didn't get a notification or anything prior to it.
Going to give this a run through and see what happens. Still have trepidation about leaving all of GPM behind.