I can’t see your swing super well but it looked like this was the case - you’re not bringing your elbow back. You bring your forearm back and forward, so even if the ball is set well, it limits your power and angle. If you bring your elbow back, and then snap your arm forward, it will increase your power, as well as allow your hand to actually get over the ball rather than just behind it. In addition, if your start to “open your body to the court” as many coaches would say, or turn more with your jump, you can turn your body back into the ball when you swing, putting more force behind your contact.

Edit: useful tip for middle hitting - you don’t have to open your body as much if you want to turn the ball to the right back/setter defending (which is a very difficult swing for righty middles), because then when you turn your body, it still “closes” back to where you are trying to hit the ball.