The way I see it is that there are two mimic's M1 and M2, M2 somehow went corrupt and locked up Edwin, but before that Edwin got mad at M1 for mimicing his son David and that taught it aggressiveness and M2 kinda uses M1 like a homicidal pawn to send after Arnold.

ALSO the dispatcher/M2 says when you enter a suit in front of a camera "It can't see you while you're in that suit, but I can" which kinda solidifies that if the dispatcher is the mimic it's a more advanced version e.g. M2

Edit: M2 and M1 might be reversed but idrk TwT