I agree with your friend. You're right, your form isn't that bad. Your back is fairly tight and you move the weight fine. But there is no leg drive. You need to squeeze your butt. Like the entire time you are benching, try and thrust your hips up off the bench, like you are doing a glute bridge.
Then, move your feet back far enough so that, with your heels planted, no matter how hard you are squeezing your butt and trying to push your hips up, they can't actually leave the bench. That is leg drive. By doing that, you create tension in your lower body that substantially increases your benching power. If you can Get the hang of this, and feel out for yourself how pressing into the floor with your heels and squeezing your butt with a tight back allows you to transfer energy through your whole body into the bar, then I agree you could instantly get a pr, AND it is going to help you make gains a lot faster.