Maya Addon Doesn't properly compute distance along the camera's forward vector

[AnsonSavage]

This one updates dynamically but doesn't properly compute the focal length (will be wrong if the target object isn't near the center of the camera's focal plane):

float $distance = pow(pow((camera1.translateX - pCube1.translateX), 2.0) + 
                         pow((camera1.translateY - pCube1.translateY), 2.0) + 
                         pow((camera1.translateZ - pCube1.translateZ), 2.0), 0.5);

    // Store initial focal length and distance when the expression is created
    // Calculate updated focal length based on the initial ratio
    cameraShape1.focalLength = $distance * 2.245459997252437;

This one (according to ChatGPT) should do it more or less right, however it doesn't seem to update dynamically.

float $cameraPosition[] = `xform -q -ws -t |camera1`;
    float $objectPosition[] = `xform -q -ws -t pCube1`;
    float $cameraRotation[] = `xform -q -ws -ro |camera1`;

    float $forwardVector[] = {
        -sin(deg_to_rad($cameraRotation[1])) * cos(deg_to_rad($cameraRotation[0])),
        sin(deg_to_rad($cameraRotation[0])),
        -cos(deg_to_rad($cameraRotation[1])) * cos(deg_to_rad($cameraRotation[0]))
    };

    float $cameraToObjectVector[] = {
        $objectPosition[0] - $cameraPosition[0],
        $objectPosition[1] - $cameraPosition[1],
        $objectPosition[2] - $cameraPosition[2]
    };

    // Calculate the distance along the camera's forward vector
    float $dotProduct = ($cameraToObjectVector[0] * $forwardVector[0]) + ($cameraToObjectVector[1] * $forwardVector[1]) + ($cameraToObjectVector[2] * $forwardVector[2]);
    float $distance = $dotProduct;

    // Store initial focal length and distance when the expression is created
    // Calculate updated focal length based on the initial ratio
    cameraShape1.focalLength = $distance * 3.297392606418606;

Any help I could get with this would be awesome!