I see a lot of aspiring artists burn themselves out and lose every bit of enjoyment they had for doing art by forcing themselves to just focus on studies all the time, and I don't know who convinced you to do that, but PLEASE go back to drawing stuff you actually want to draw!

The notion that you can't learn within your comfort zone is absolute bogus and I don't know who perpetuated that myth, but improving your work is hard enough without purposely making it less fun as you go, certainly in the beginning.

Did you pick up art because you watched a series whose characters you really love and you'd like to be able to draw them? Then do that! Use references as you go, do your research, do studies relevant to drawing those characters and immediately apply what you've learned.

I promise you whatever skills you pick up as you're doing this fun thing that you actually want to do will carry over into the next thing you want to learn. Don't worry about style, don't worry about "being unique", and if you don't have to, don't worry about monetizing yourself.

The most important thing is that you get into the habit, that you figure out how you personally absorb and retain information best, and that you keep finding whatever new cool thing you want to excel at. Which is considerably easier when you're actually enjoying yourself.

When people say "it's easier to learn stuff you're young" we think of time, energy, responsibility etc. and that's all true, but a big part of the reason is also that as kids we don't give a sh*t about what the "right" or "most efficient" way to learn is. We just do what's fun.