IIRC the Xbox One launched a year later than the PS4 in Japan, and that one week of its launch week it outsold the PS4, then sales immediately fell off. I think that was the last time Xbox outsold PS in Japan for a week.
Demand for Xbox in Japan remains low (quite low, if we are being honest) but it is much healthier than the demand for the Xbox One was. I think the Xbox series consoles will pass the original Xbox in lifetime sales in Japan, and I don’t think 1,000,000 lifetime in Japan is off the table for the Series X|S, if Microsoft really tries. The Series S could fill a niche for a tiny, inexpensive western AAA and indie game playing box that I think could make sense for some people in a market like Japan