The GIF is quite difficult to be inspected for your scratch pad, but here is my way of rotating the decal.
You can replace the AngleInDegrees with your own parameter with the range of [0,360].
Edit: Changed “From Vector” from [1,0,0] to [-1,0,0] for the correct facing of the decal. Otherwise the resultant orientation would be flipped, which is particularly problematic when calculating the correct normal.