Theoretically speaking, solid geometry is more difficult to learn than plane geometry, but you are just the opposite. As doctors often say, your illness is not a disease, because your thinking about solid geometry is deeply rooted in your mind. When you meet plane geometry, you will always think of solid geometry consciously or unconsciously. As you can see from what you said above, no straight line and plane are perpendicular in plane geometry. Just jump out of the circle of solid geometry and recall the feeling of plane geometry in junior high school and middle school. I believe that plane geometry is definitely not a problem for a person with such a good sense of geometry.