Rear right rattling noise when braking

[Qasimateen]

Whenever I hit the brakes slightly, I hear a rattle noise coming from my rear right. The rattle usually goes away when I press the brake down very hard.
This whole time, I thought it was my brake shield hitting against the rotor but after bending the shield back, the noise will always be there no matter what.

To investigate further, I lifted the rear side of the car so I can really see what’s going on. With the wheels out and driving slowly while braking, I notice my entire rear right wheel base is shaking. (See video below).
https://youtu.be/QaL-MALleBA?si=f0-rg2ctvKXATebC

Is it the control arm bushings that are bad? Perhaps the axle is bad?
Not sure myself but was hoping if anyone knows the possible cause for this type of issue.

FYI, I checked the rear left side and this behavior isn’t occurring so the rear right shaking would be the culprit to the braking rattle noise.