Hi,
The Background Lower Parallax has a scale option which is missing in the Background Upper Parallax settings. Instead of the scale option for the Upper it repeats the direction options, a bug which was reported back in 2021 here.
I know this but is already in your queue to be fixed. However, I’d like to request a work around for the scale in the meantime please. Currently there is no way for me to control the speed of the parallax for the upper layer, unlike the lower layer in which I can control that via the scale setting.