I have been at red once when there were more formal problems(ex tree dp) at contests, but now I need more idea, ad-hoc, math, greedy. I tried to solve difficulty 2300~2500 and upsolved for years but cannot solve it well.

I know there is no such secret tip to be red, but I want to ask "Am I too stupid to solve those good idea problems? Or do I need more time? Or am I doing something wrong?"