The subfloor is important.

Many installers used PE foam 3mm which will sink or shrink over time causing the level to dip from 3mm to 1.5mm. As a result, the SPC will crack at the joints.

I used a 3mm pure rubberized carpet underlay for stability. Slightly more expensive but it will not disintegrate over time. Plus, u can move it to another location (suitable for rental properties).