When you sleep on your back , or your pillow lets your head tilt forward , your neck angle shifts. The soft tissue at the back of your throat collapses
inward. The airway narrows.
Air forces through a smaller opening at higher speed. That turbulence makes the tissue vibrate. That vibration is snoring.
It's not random. It's not genetic. It's mechanical , and it happens every night your posture isn't corrected.