A mixed race Japan squad would be world class honestly. With their technical prowess and physical bodies. France, Germany, Belgium, etc. all feature superb mixed race athletes (e.g. Mbappe, Lukaku, Boateng, etc.) Cause let's be real, the Japanese body can't keep up with South American, African, and European bodies. Athleticism is a huge part of sports whether we like it or not.
Correct me if I'm wrong (i have limited knowledge), but yea I think it's a sad reality.