Justification (derivation) of formulas from statistics used in machine learning?

Question

Machine learning

Hello.
I study mat. statistics in the context of "machine learning". In many courses and textbooks that came across, they only mention the method or criterion used (I looked at at least five of the books with the words "math. statistics" in the title, from the topics on the toaster - at least Recommend books on mathematics? and How to understand mathematics and statistics ?
Examples of concepts encountered: RSS (residual sum of squares), gradient descent, logistic regression, etc.
I figured out RSS through a video on khanacademy, on the descent I found a good explanation on the
"Artificial Intelligence and Machine Learning" channel. But so far I have found them ... and how many more topics are ahead. It's quite tedious to search.
Please tell me a resource, a book, blogs, where there is a derivation of the formulas encountered.
Thank you.