If you believe Paint or any other circle drawing program isn't accurate then let me demonstrate in a 3d model using 3d blender. I have drawn a perfect circle using 12 cyphers and if you connect them it will make your circle. However, in real life they are bunched together like in the MS Paint model. This is because each atom is so tiny that each atom does not have enough sides to form the perfect circle. Basically in the 3d model because there are 32 sides for the cylinder that means it can attach on whatever angle. However if they can only attach on the sides or direct diagonal that is where the MS Paint model is by far more accurate. This is really going into atomic physics now. You will find that atoms cannot attach on any angle that we can write down (example 98.35869049696 degrees). However they can attach on a certain number of degrees. It is due to this limitation that pi will never be true. Why? Take a look at my diagram, all the circles are at different angles to each other. what if you had 4,000,000,000,000,000,000 points in that circle. In reality that is only a few cm's. Then you would have to have some atoms beside each other and above each other to be able to make the perfect circle. And remember that atoms need to all be attached. That forces another limitation. If they need to all be attached and they have very few sides then that will also force the atoms to go above and beside each other. Just keep that in mind.
Again : You cannot ever draw a perfect circle using a software
because they are all made up by pixels, and Pixels are rectangles.
Also realize that there might never be a perfect circle.