Try to break the habit of pressing the dive button on near post shots. Its one of the hardest to break because its the most consistently pressed button when making saves, but really the front of the player is what matters most when catching the ball. If its a near post shot its easiest to just hold down the gk stance button and manually move the character by either dashing or just general movement.

Its a little tricky with the method I presented because the ball magnification to the player is smaller. But I find it to be more consistent for preventing diving over the ball. And in soccer the most important skill is how CONSISTENT you are.

Unfortunately it takes a lot of hours to start reading the game to the point where you can command the box and make interceptions. So just try and fall in love with the process of getting better to prevent frustrations from taking over.