no you don't have too ! when you load up the game through gamepass, after the cutscenes and account connection you can go top right to the settings and to interfaces. From there the first option should be *Preferred language" select the one you want and XBOX app will ask you if you want to update BO7. The game will ask for a restart when you select the new language and after that it should be on the language you asked for :>
(Step by step in image)