Atomic Habits works for me the best, I also just read ‘The Gut’, a healthy body also helps with better intellect.

8 lessons from "How to Learn Almost Anything in 48 Hours": Focus, memory hacks, prioritize, active learning, spaced repetition, sleep well, create a great study space, and adopt a growth mindset. BOOK: https://amzn.to/4bZ9Qdk

Focus on Perspective by Meenakshi Suri helps to fine tune focus for solving problems when confused or overwhelmed. Check Amazon

The Power of Now, Think and Grow Rich, The body keeps score, Unfuck yourself, Sell or be sold, The Art of war, Wealth can’t wait. Just to name a few. I would start with The Power of Now, if you haven’t already read it. However, don’t just read, study these books.