I think that my biggest issue when drawing is that my line art looks unconfident. I'm somewhat okay at rendering, but when it comes to line art, I falter hard. Here's a drawing I made super quickly, in under 30 minutes, as an example. I attached the timelapse as well.
Even for drawings I spend a long time working on, the line art still isn't good, in my opinion. I want to improve, but I don't know how to make my lines more confident. Even practicing a lot isn't helping much.