I recently got my diamond subscription, so I spammed puzzles right away. I think I was on 1500 and immediately got into 2000-2100. However, while I was in that elo range, I felt tired and was kind of hyperventilating from solving some of them, keep in mind that I wasn't able to solve most of them and my average time of solving was 7-15 seconds. How can I improve my grounds in this area of chess? Any suggestions?