I watched Tuchels Interview when the signing was all but confirmed and from the looks of it, it was not like Tuchel did not rate him, but Tuchel said Gravenberchs best position is the 8 and that does not exist in Bayerns system (according to Tuchel), so Tuchel wanted to convert him to play in the 3 of the 4-2-3-1, but thats where Bayern have the biggest competition (Müller, Musiala, Gnabry, Coman, Sane) So thats why he did not get play time. Also seemed to imply that Gravenberch was not willing to be converted to a Winger/wanted to play in his preferred position.
I think he will get a lot of game time for us and will be class. And if not, he is still young, we didn't pay too much and have other great midfielders.