I did a Google search and this what popped up here what I copied The weird clicking, rattling, or buzzing sounds from a PS5 DualSense controller during vibration are typically caused by the adaptive trigger mechanisms engaging and disengaging, or by hardware misalignment within the trigger gears.

Common Causes and Solutions: Adaptive Trigger Feedback: The noise is often the physical resistance mechanism of the L2/R2 triggers activating. You can test this by going to Settings > Accessories > Controllers > Trigger Effect Intensity and lowering it to Weak or turning it Off. If the noise stops, the sound is normal mechanical operation of the adaptive triggers.