for the rattling sound that you hear when you shake the optical image stabilization "OIS"
its the one managing when you are recording or capturing phone to be at a stable position
there is no way for it to be tightened up because it is controlled a gimbal-like inside the device.
and when you are capturing a video it shouldn't make any noise because the electromagnet will be turned on and stabilize the videos and photos that you are trying to the.https://www.samsung.com/global/galaxy/what-is/optical-image-stabilization/
Be sure to click " ✔ Accept as Solution" When you find an answer that works for you
Ya I have the same thing but I don't think it's a real issue since it's just the camera gimble moving around