Incorrect beginning Z movement I just bought an Ender 3 Max and from the start I knew something was wrong. I figured out the problem: it is with the first few millimeters of the Z axis movement.
I turn on my 3D printer, go to prepare, move axis, move Z, move 1 mm.
Then I tell the printer to move up 1 mm. But in reality it only moves up 0.3 mm.  I then tell it to move up another millimeter, except it only moves up 0.4 mm. When I tell it to move up another millimeter, and it moves up only 0.45 mm.  I then tell it to move up another millimeter and it moves up 0.6 mm. And then anytime after that when I say to move up a millimeter it actually moves up a millimeter.  Below is a little chart to help you understand what is happening.
Set height | Actual height
--------------------------
         0 | 0
         1 | 0.3
         2 | 0.7
         3 | 1.15
         4 | 1.75
         5 | 2.75
         6 | 3.75
         7 | 4.75
         8 | 5.75
         9 | 6.75
        10 | 7.75

As a result of this error on my printer, the test prints I have run so far are splayed out and uneven at the bottom, making my prints warped at the first 5 mm and several millimeters shorter than they should be.
Your printer probably has an issue with binding in the lower region (binding means extra friction possibly causing the Z stepper to skip steps). Disconnect the lead screw an manually move the X gantry up and down. If there is binding, you need to find why this happens, with the unfortunate design of the Ender, many people experience issues when the rollers on both posts are not correctly installed.