In their defense, there are sometimes good explanations in the comments when you get things wrong and those end up helping. Though, I agree that it isn't content that is provided or verified by their team and it is something coming from the user community.
Agreed, without the number of years of experience (there is possibly a loose correlation with the levels indicated) it is hard to make sense of the data
Knuth's approach takes an extreme and of course someone like him can afford a secretary but for those of us that can't, Cal Newport's book Deep Work offers some pretty good suggestions on how to handle the plague of emails while being prolific in the work output that he generates. Key among the is the batching technique which others have mentioned but I'd highly recommend reading Deep Work to get a good balanced view on the subject
I'm surprised that no one has yet mentioned Andrew Ng's Machine Learning course on Coursera and to go a bit deeper, his deep learning specialization on Coursera as well. Along with the programming assignments it's a solid way to get your feet wet. And definitely second the suggestion of the fast.ai courses as well