If you restrict it based on up/down and left/right then you won’t get a target circle, you will get a target box.
You want to normalize your offsets and multiply them by the distance from the center (Pythagoras using your X and Y offsets) but clamp the distance to a maximum radius first. That will give you a new X and Y which should be good to use in a FindLookAtRotation.
Here’s the rub. You also appear to have another problem. You are using your offsets to modify a world position. In order to do that you need to get the offsets relative to the shooter. It’s not that hard, tho. Instead of just using your X and Y offsets, you want to get the up and right vectors of the aim rotation. Then multiply the X offset by the right vector and the Y offset by the up vector. That (and what I said above) will give you the right offsets to add to the world position and then find the look-at rotation.
