If you're doing self-study... In my opinion you'll see the most progress if you narrow what you study down to one or two subjects and FOCUS on them for a period of time (a few weeks maybe).
Trying to do too many things at once is bad because: you get overwhelmed and lose sight of the goal, it takes far more time to plan how to study each subject, and you end up making slower progress on each subject.
Studying 5 things at once at school/university is possible only because we are forced to, all of the planning of the material to study is prepared for us, so we just have to do the work and absorb the information without having to worry how or what to study.
Tldr: identify what is essential for the kind of art you want to make, and focus on 1-2 subjects at a time, and cycle what you study around so you don't get burnt out.