By just replacing X and Y axis pom wheels with linear rails and upgrading the hotend to microswiss flowtech made my neptune 4 plus a machine I needed. This is a first try print without any additional calibration. Moving print in place. In retrospective I should have bought a creality k1 though

Looks deliciously 3d printable

I will never ever (hopefully) get a machine like this that uses pom wheels on axis controlled with belts. Almost constant need to calibrate and re-tighten them is frustrating enough to make me try not using the device.