I finally had the option to transfer all my uploaded and playlists to YouTube Music. I initialised the transfer and all went well. It’s nice to have access to my albums that are not on the streaming services in YouTube Music; its interface is improving and recommendations too - not as good as Spotify yet, but I’m not going to pay for two music services. A separate tab for upload music oddly makes sense as I was getting weird duplicates in the old Google Play Music interface.
One issue I encountered was a weird bug where I lost the left side bar in YouTube. I had to delete my playlists in YouTube Music before the side bar returned in YouTube.