The Obstacle Is The Way by Ryan Holiday is an accessible introduction to stoicism. Think of it as a mix between ancient philosophy and modern self-help. What would Marcus Aurelius do when your stock price dips? The mix of anecdotes and timeless wisdom is direct and conversational.
This is a great read and one I've shared with friends. They say they want to learn more philosophy but are really saying they want real world utility/advice to improve their lives. Therefore this is a go to book to share.
Neon Fever Dream