Most likely causestemperature, retraction, travel speed, and filament dryness.
Printer focusElegoo Neptune printers are popular Klipper-based FDM machines where first-layer, flow, acceleration, and slicer profile tuning matter.
Slicer checkReview Orca Slicer, Cura, Bambu Studio, PrusaSlicer, or the slicer profile used for this printer before changing mechanical parts.