When I was making the armor, I saw some things that would cause a problem for me, parts that should move with certain movements, like the knees or arms, the upper plates of the hands, and so I used a simple solution: ELASTICS.
In some cases, it is the only thing that works, as you will see in the video.
REMEMBERING: Not everything works the same for everyone, you need to work and do tests.
Basically, after printing, I tested with some elastics, gluing the tips internally on the forearms, so that when moving, only the center of the piece goes down and the elastics make the opposite movement, to return the piece to its original position.
And in the end, a good result, with no pieces missing and still with movement.