Inconsistent layers ech every 4mm with belted Z - V-Minion | TicTac Custom

Hi 3d printer owners, I got a weird issue on my custom V-minion printer. Already built belted Z, double mgn12 rails and its moving smoothly by hand. Any suggestion about this? What I have done: PID everything several times.. Rebuilt everything and make sure frame is squared Change differences type of extruders Change new TZ 2.0 Hotend Change all Z pulleys and bearings Nothing can solve it, Im really stuck now. Thanks