Up here we have the latest Japanese trailer for upcoming PS4 games and if you can endure weird rapping up until about 1:35 (or if you just skip ahead on that portion), it's possible to track down the star ratings of LOSER, one of the new J-Pop inclusions of the game, which is rated 3/5/6/8.
Thanks to taikojoe from the Taiko no Tatsujin Discord for the find!