Japan needs to modernize by going unmanned robotic. Much smaller nuclear powered units that can operate autonomously. (Yeah, I see the negatives, but Japan will never be able to match China any other way.)
I’ve been to China a few times—not impressed. Their “new” buildings start falling apart almost immediately. And, contrary to popular opinion, they tend to be very disorganized. In many ways they are the opposite of the Japanese. I think the Japanese probably have a few tricks up their sleeve and would clean their clock.
Japan is doing big things with drones - given the ranges in question I see that as a game changer in the regional naval theater.