It's always a good idea to start with anatomy studies and pencil/line control, so that's what I'd suggest. Reference the shit out of everything, break down the human form into shapes, look at how it's constructed. Buy a crappy little sketchbook and just draw stuff in front of you. Draw your family and friends, go out to a park or a café (when things go back to normal) and just draw people around you. Draw them as you see them too. Don't try and stylise it. I get that you said you don't want to draw in a realistic style, but learning to draw things from sight and learning basic realistic human anatomy are both important for drawing things from imagination and for drawing in a stylised way. Think of it like this; you have to learn the rules before you can bend them. It may seem boring, but having a good foundation is super important. (This is how you improve at shading also, study light and how it interacts with forms.) For line control, this is something you will just build up over time, but there are things you can do to help you improve faster. Draw straight horizontal lines of varying lengths (1cm, 5cm, 10cm) and notice how your fingers, wrist, and elbow all move and work together. These parts of the body are what dictate line control. It's also a matter of confidence. Try to maintain a firm but relaxed grip on your pencil, and try and move confidently and quickly without pressing down too hard. I'd also recommend switching over to a pen for at least some of your drawing practice (fineliner or fountain is best.) Removing your ability to erase will help you improve your line control and confidence much faster. Set up a pinterest board for references/tutorials and also for artists/art you like. Pick out elements you like from their work and try it out in your own. Look up tutorials and process videos on YT as much as you can. A personal favourite of mine is Sinix Design. His anatomy quick tips series is super helpful. Always keep in mind that at the end of the day, drawing is supposed to be fun. Try to avoid burning out by practicing too hard. Taking breaks is super important, and just because you're not drawing doesn't mean you aren't being productive with your art. Spending an hour or two watching YT tutorials or browsing the internet for art you like/inspiration is also being productive. Sorry for the wall of text, hopefully this isn't too overwhelming.

Just remember the rule that you can't bend reality before you understand it. You need to use lighter lines first to slowly learn shapes and imperfections or things, if you start out with a badly done heavy line it's a mistake that even if corrected can stand out.

This may seem offtopic, but does anyone know how to view older PMs? Red sent me some diagrams I want to pull up, but I can’t scroll back far enough to find them. Beyond grabbing those diagrams, I’d need a sample of your work to offer any specific advice.

Practice proportions before anything, then move on to details.

Got a sample?