You're focusing on the wrong things. Have you ever heard of gestalt? Essentially, it's the idea that we see the whole before we see the details. No one's going to care if a leaf doesn't look good if the whole environment is convincing. People aren't telling you to do realism because we want you to stop stylizing, but because you're still unable to represent form in a convincing way. There is no better way to learn this than to take something from real life and try to translate into 2d. Take a look at Andrew Loomis, who breaks down extremely realistic portraits into basic shapes. That is the basis of understanding form. The reason "good" artists can seemingly draw anything is because they understand how to break it down to its simplest shapes. That is what you need to start worrying about.
On another note, in case no one has ever taken the time to say this to you: It is okay to not have a style. It is okay to make bad art. Every time you start heading in the right direction with realism, you add a comment like "BUT I'M STILL GOING TO STYLIZE OKAY". Genuinely, it is okay to not stylize. Styles are very easy to pick up and are ultimately worthless, skill is not. When you try to stylize your practices, you aren't actually looking at what you're drawing and you're actually making your training less effective. Take some time to make some really terrible stuff from life. No one will disrespect you for it, and if they do they're assholes that you don't have to listen to. Don't be afraid of making bad art. It's the only way you can end up making good art.
