Go to a store that sells appliances, like a refrigerator. Ask them for the cardboard box that the refrigerator came in. Take the large cardboard box home and cutout the figure of a batter. Spray paint it black. Prop the cardboard figure up - right or left handed batter, and the pitch to a backstop net or something. Focus on the net or whatever target that you’re using.
You’ll probably nail this cutout a few times so expect to save all sides of the cardboard box so you can make more cutouts.
What’s happing is this, you’re vision is picking up the batter and that vision is in the total picture - including your target. In other words, the batter’s presence is overpowering your concentration. You’ve got to train yourself to focus only on your target - excluding the batter.
This is an issue for a lot of pitchers - more so that most people think.