I still think this forum is overstating the effect of Japanese games on the overall perception or impact of the brand. I believe past Xbox bosses' reflections that they spent too much time trying to win over Japan when they should have been focusing on their strengths remains very applicable. Sure, quintessentially Japanese games are starting to really gain footholds in the West. But.. that doesn't mean the average Japanese game/dev ever makes much of a splash. (I also notice the focus of my Japan-focused pessimism keeps shifting, because I deep down still really want MS to go big in Japan/Asia. Anyway.)
Investment in Japan has to be targeted. That could be targeting a specific portfolio of games from known developers to make exclusive to Xbox. Or, it could be making a larger acquisition of an established group that can handle overall management and infrastructure and strategy for the region. But, I honestly don't see why either of these strategies should be a priority, though.
I'd much rather they spend the money (business, marketing, AND dev support - since most Japanese devs don't regularly work on Xbox) on bringing over franchises that traditionally skip Xbox. Not to steal them from Sony or Nintendo, but just to show that there is a legitimate business case to work with and release on Xbox. If and only if that is established will Japan come willingly. And fortunately for everyone, you don't have to spend a ton of money on owning the dev or buying the exclusives in order to prove that. Target several smaller games at a variety of devs, work closely with them, market the games heavily with game pass, and tout that success.