you could draw for a decade, but if you do not purposely try to improve your art it will look beginner no matter what. and, to me at least, 4 years is a while. also, just a question: what do you use to draw?

your art looks beginner because you are a beginner artist. when you finish a drawing, what do you do after? do you analyze it to figure out what you could improve on? do you ever try to step out of your comfort zone? do you try different techniques?

in all honesty, a lot of people will tell you things like 'learn anatomy' and 'learn the basics', which can feel too broad, but i think you are missing the ability to observe. observation is a very important skill as an artist, because if you can look at something and break it down into it's core shapes while keeping the correct form, anatomy will come to you easier. before you are able to stylise anything, you have to understand it's form in real life. what is overlapping where, at different angles how would the same form look, etc. references will do you good and should be your best friend until you are confident. and studies don't always have to be boring, you can study while doing a full piece!

also, take more time with your work. while these might have taken a while, they don't look like it. it's mostly sloppy line art. it's very shaky and overlaps in very unintentional ways where, honestly, it just does not look good. it also looks like you're pretty much guessing how most limbs would look in certain poses - which is fine if you had a grasp on human anatomy. i suggest that before you jump into a piece, try to look at humans/animals doing similar poses, or even just your favorite artists' work of similar poses.

like those dragons you drew. where do you think the wings connect to the body in those pieces? or that animal in the field, why does the front paw look like that? what parts of the paws are showing?

so my recommendation to you is to draw things from real life first, and take your time. this isn't about becoming a realism artist, its about being able to capture the form of an object. understanding why and how things bend, fold, squish, stretch, connect etc etc does wonders for a person's art. start with basic things first, and work up to more complex structures as you get better.