Need help creating a graph that can automatically keep the x & y axis in the same scale

From that chunk of code, seems like you only need:

    With myChart
        With .Axes(xlValue)
            .MinimumScale = yourMinScale
            .MaximumScale = yourMaxScale
        End With
        With .Axes(xlCategory)
            .MinimumScale = yourMinScale
            .MaximumScale = yourMaxScale
        End With
    End With

Amend and add to your existing code that creates the chart?