If you want books that can help you learn to think, you can't do better than the classics. I suggest Plato's dialogs or the Analects of Confucius. You may find them more accessible than you expect. They were excellent teachers.
Here's a good translation of Plato by Benjamin Jowett: https://oll.libertyfund.org/titles/plato-the-dialogues-of-pl...
And one of Confucius by James Legge: https://oll.libertyfund.org/titles/legge-the-chinese-classic...
Both translations are from the 19th Century and so have entered the public domain. But both are also often considered the best English versions of these works, even today.
(Note you can download a facsimile pdf of the original book, and print it out as you go. I prefer to read anything long-form that way. Better for concentration in my opinion).