A question to clarify: if you can’t see yourself using the information/theorems you are studying and you aren’t motivated on a particular topic, why are you investing the time? Secondly, many textbooks are tedious and not particularly useful for self study. HN has numerous threads discussing the best textbooks in a variety of subjects. I have found these threads quite useful in selecting textbooks to review. Not to sound critical but perhaps your self study program needs a more orderly curriculum. Again, numerous threads here and elsewhere address paths to acquire the requisite knowledge.