I updated to version 10.X from version 9.X and the Final Fantasy playlist doesn't have the new songs, why?

This is because you already have an edited version of the playlists. You can either add the songs manually, or delete/edit the file mods/musicoverride/playlist_override.json

My resolution is too low and many UI elements are cropped

I'm sure there's a better way to handle it, but for now, click "Settings" > "UI Scale" and select "Small" and restart. This should handle ~720p resolution. If you use even less than that, it's not supported at this time.

Some songs aren't showing up in Battlefield Music Selection anymore

A bug was introduced in patch 1.42 due to the discovery of new hashes and some values may have been lost. The manual fix is: under PRC DBRoot:

• is_selected_original: set to true
• is_selected_movie_edit: set to true (optional)

If you edited DLC original songs, it is also possible the following values were altered:

• dlc_ui_chara_id
• dlc_mii_hat_motif_id
• dlc_mii_body_motif_id

If the values aren't there, the easiest way to fix is wipe MusicOverride/core_game_override.json and restart.

This is a one time fix. Future songs won't have this issue.

I'll provide a command in software to automatically reapply is_selected_original / is_selected_movie_edit soon.