You gotta use your body for every single stroke, because the more mass you involve in the stroke the more momentum (including angular momentum) can be transferred to the ball. It is not simply a question about bat speed, because momentum = mv (it's a function of both mass and velocity). Maybe that's also why fat heavy guys tend to have harder loops 

So for eg even for your bog standard push, it's not just an arm only stroke, to really upgrade it you should rotate your body into the push slightly to involve your entire body, this has a significant impact on the spin quality of your stroke, and reduce your arm backswing significantly. Same with serves, you gotta stay low and throw your body weight into the ball (rotate into it). Same with the forehand flip too, you gotta rotate into the ball (even if it's a small movement, it's super important). 

The other point is about weight transfer in the FH loop. For max power, there must be true weight transfer, ie at max backswing you should feel almost all the weight on your right foot, and at followthrough you should feel almost all the weight on your left foot (and it should be tiring af lol). And as you transfer the weight, it is very important that your right thigh comes forward (not just upwards) as you rotate forward into the ball. If the right thigh doesn't come forward then you didn't transfer the forward momentum from your body, only upwards.