Machine Learning

I'm trying to learning machine learning from a more mathematical/theory side of machine learning just so its easier for me to understand AI/ML papers that are coming out just to keep up with them. I would say that I have a basic understanding of AI/ML but more so on the applied side like in Keras, TF, PyTorch somewhat but I feel like I am lacking on my understanding on the mathematical side of AI/ML. So any books and course recs for that?