When you shake the S21 Ultra (probably other Smartphones as well) you can hear a rattle.Its not a faulty device or a loos screw, its actually the camera shaking! Yes, the camera has a stabiliser to take videos more smoothly. Now you know.
The rattle is the camera lens, I've got an s21 Ultra and am experience the same thing. Dont stress though it should rattle as its the stabiliser, stress when it stops rattling xD
