Does this achieve what you are trying to do?

With my code you have to define the center and max height and width.

import numpy as np

def pad_array(original_array, center_coordinates, max_width, max_height):
    w1, h1 = original_array.shape
    cx, cy = center_coordinates

    # calculate padding on each side first
    pad_left = max(0, max_width // 2 - cx)
    pad_right = max(0, max_width - pad_left - w1)
    pad_top = max(0, max_height // 2 - cy)
    pad_bottom = max(0, max_height - pad_top - h1)

    # then pad the original array
    padded_array = np.pad(original_array, ((pad_top, pad_bottom), (pad_left, pad_right)), mode="constant", constant_values=-1)

    return padded_array

original_array = np.array([[-1, 0, 5], [0, 0, 0], [5, 5, 5]])
center_coordinates = (0, 0)
max_width = 5
max_height = 5

padded_array = pad_array(original_array, center_coordinates, max_width, max_height)
print(padded_array)

center_coordinates = (1, 1)
max_width = 5
max_height = 5

padded_array = pad_array(original_array, center_coordinates, max_width, max_height)
print(padded_array)

My outputs for center 0,0 and 1,1 are as follows:

[[-1 -1 -1 -1 -1]
 [-1 -1 -1 -1 -1]
 [-1 -1 -1  0  5]
 [-1 -1  0  0  0]
 [-1 -1  5  5  5]]

[[-1 -1 -1 -1 -1]
 [-1 -1  0  5 -1]
 [-1  0  0  0 -1]
 [-1  5  5  5 -1]
 [-1 -1 -1 -1 -1]]

You can always make the width and height to the share the variable like size as well like this

import numpy as np

def pad_array(original_array, center_coordinates, max_size):
    w1, h1 = original_array.shape
    cx, cy = center_coordinates

    # calculate padding on each side first
    pad_left = max(0, max_size // 2 - cx)
    pad_right = max(0, max_size - pad_left - w1)
    pad_top = max(0, max_size // 2 - cy)
    pad_bottom = max(0, max_size - pad_top - h1)

    # then pad the original array
    padded_array = np.pad(original_array, ((pad_top, pad_bottom), (pad_left, pad_right)), mode="constant", constant_values=-1)

    return padded_array

original_array = np.array([[-1, 0, 5], [0, 0, 0], [5, 5, 5]])
center_coordinates = (0, 0)
max_size = 5

padded_array = pad_array(original_array, center_coordinates, max_size)
print(padded_array)

Then you can just get your agent to change the center. Just leave the max_size as a constant 5 like this.

original_array = np.array([[-1, 0, 5], [0, 0, 0], [5, 5, 5]])
center_coordinates = (0, 0)
padded_array = pad_array(original_array, center_coordinates, 5)