I've been trying out blender, following along with the donut tutorial, but it feels like I am just copying and not learning much. I often get sidetracked and try to make something a bit different to the tutorial but its just so difficult and never works..
For example, I wanted to create a donut, but with no middle (like the donuts with filling inside). I spent so long trying to make the initial mesh and when I got something that looked correct, viewing it with textures showed a completely broken, and stretched out in places image.
Any ideas for getting over this learning curve? Is it just watching YouTube tutorials and following along until I randomly discover new info to use in other projects?
I'm the exact same as you and I don't really enjoy plainly following tutorials. What might work for you is to keep doing what you're doing, and let that shape your growth.
Using your experience with the donut tutorial as an example, you went through the effort of doing something different, but all your textures are stretched out. You might ask a beginner 3d/blender community why, and they might tell you about how uv mapping and texturing works. You can take that information and follow up by watching a tutorial on texturing.
3d art is definitely hard to get into, and the biggest challenge when growing your skill is keeping your motivation and practicing as frequently as possible. Every issue you can see with your models is an opportunity to grow, and you can become amazing if you keep it up!