My experience in learning math is that the textbooks try to provide what is right. And what is right typically becomes excessively verbose to the point that the main idea gets lost in the rightness. This is what in person coaching gets you. You get the intuition of the idea, ignoring all the nitty gritty and only when you have a firm grasp of the intuition do you explore what this intuition also means for different cases and hence the nitty gritties.
Having experienced this myself many times over, I now know exactly what to look for in a book when I am self learning. I don't know how this skill is to be taught but if remote learning was to succeed, different methods of learning needs to be outlined and taught to the students and get them to learn to select one appropriate for their learning styles and subject.