A few books I recommend to therapy clients--that aren't typical "self-help" books:

The Miracle of Mindfulness, by Thich Nhat Hanh. It's a series of letters he wrote to a fellow monk dealing with the atrocities of the Vietnam War and ways practicing mindfulness could help them weather the storm.

Man's Search for Meaning, by Viktor Frankl. Holocaust survivor who discovered the main distinction between people who died of no specific cause in the concentration camps and those who survived was that the ones who survived created meaning in their lives. Those who had no meaning or anything driving them simply died.

The Daily Stoic, by Ryan Holiday. One page a day--anyone can fit this book into their schedule. A brief quote by an ancient Stoic, followed by Ryan's modern application of it.

All are solid, easy, hyper-practical reads and ones without all the "guru" bullshit.