I’ve been stuck at 2000 rating for about 40 yrs, a huge break for college and a career. But I was never able to get to 2200. I’m retired now and really spending time to get to that goal. In reflection, in my youth, my analytical skills were pretty good. With age, I think they are weaker based on results. I’m also less competitive. My pattern mastery is really good. So, I think of my game performance as my wisdom allows me to compensate for my loss of analytical power. I do think formulating a middle game strategy is an area that can help improve my results and that is my primary focus.

Why not both?

I played chess until ~15yo, but I have more experience in Math Olympiads. My guess is both. Thinking more efficiently in a high level, and also improving the concentration and time to get tired to think more.