What is the magnitude of the inaccuracy that you’re seeing?
The Ender 3 will have some X/Y inaccuracies due to how the belts are implemented (ie they’re not always parallel) and the inaccuracies are not linear and will change with the position of the gantry and print bed.
For example, when the gantry is in the center, you will get most accurate movement because the belt is closest to parallel and the angle the belt is off is even at both sides. When the gantry is at an extreme, the belt closest to the edge will be at a much larger angle than the other side and will move less than if the gantry is at the middle (it’s a cosine error - a movement of the hypotenuse, the belt itself, will move more than the adjacent side, the V-Slot rail with wheels).
I did some measuring and calculations once out of interest and you can get 0.3mm to 0.5mm errors (depending on the print bed size) in movement at the edges compared to the center of the bed where the errors will be on the order of a hundredth of a millimeter.
How do you propose to calibrate the movement considering that the errors are non-linear? I’m not sure what you mean by this being a “standard issue”.
Also note that the print itself will shrink, grow, warp for a variety of reasons (cooling, uneven cooling, humidity, phase of the moon, etc.) - what exactly are you looking for? I suggest that you read the link that @sineos suggested.