What is the best way to get the color of a pixel?

Question

Python

I'm using getpixel to get the color, but the problem is that getting the color of a pixel doesn't always show the same result. (Colors differ) result (colors of squares from getpixel ) : original getpixel

r, g, b = screenshot_data.getpixel((center_x, center_y))

Then I find the nearest color, there are 6 colors in colors. But due to the large spread of cyan / blue or pink / white colors, it assigns an erroneous color.

c = 0
    for color in colors:
        diff = 0
        for i in range(3):
            diff += abs(color[i]-pix[i])
        if diff < 70:
            return names[c]
        c += 1

I thought about the idea to make a range of colors / shades and check if the color from getpixel is in this range, then return the name of the color. But I did not find a ready range of RGB colors on the Internet.
Tried via pyautogui.locateOnScreen. He's point blank in the 57x57 region and can't figure out what it is.

for key, value in images.items():
        elem = pyautogui.locateOnScreen(value['path'], region=(x, y, x+CELL_SIZE, y+CELL_SIZE) )
        if elem:
            print('Meat found!', elem)
            draw.rectangle([(s[0], s[1]),(s[0]+CELL_SIZE,s[1]+CELL_SIZE)], width = 1, fill=value['color'], outline='red')

In short, I need to determine exactly which of the 6 colors (red, blue, purple, white, green, yellow) a cell belongs to. My problem is that getpixel does not perfectly determine the color of the cell. As a result, it turns out that when comparing the nearest colors, pale pink is defined as white, or dark blue as purple.

Do you have any ideas how to solve this problem?