I will be blunt. If you are as bad at math and spatial reasoning as you say, then CAD probably isn’t for you. You will always find it difficult and unrewarding. Design and engineering require a mindset you might not have.

As far as “cheap and easy and professional” CAD they ALL require effort to learn and money to gain entry for commercial versions. CAD is a skill and skills require effort to acquire. And it sounds as if you have no desire to put in very much effort.

For a CAD program to meet your want of cheap and simple, (professional means a lot of money and takes more than a few minutes of effort), look at TinkerCAD. It’s free and simple enough that I teach that to 5th and 6th grade students well enough for them to make simple objects. Ain’t nothing wrong with starting there and learning how to think about design and CAD before you might try and step into more demanding software.