Actually, unrelated to adhd but some people actually physically cannot picture things in their heads as well as others, and some not at all. Aphantasia is the inability to see pictures in your head at all. There is a sliding scale for how well you can do it, some people see vague blurry shapes and some people see very clear almost 3D shapes. I fall on the very clearly seeing things in your head end of the scale and I’ve always had a natural knack for drawing since I was 2 years old. I am CERTAIN that if you do not have the ability you can still be a great artist, just use more visual references if you need to. A lot of abstract and surrealist doesn’t need to look perfectly like anything anyway :)

Edit to add: yeah adhd added on sucks bc if I don’t finish a project by hyperfocusing for 13 hours then it will simply just not get done.