Unfortunately, this would be a huge task of redoing everything, as all the components are designed like that.
I do not think there is any real difference that would stop you using the EU one in the US. other than hole size. Maybe an easier option, if NxPanel would work better for you than stock, is just to get an EU one and mount in a EU size hole? Just a suggestion. But doing a version in a different orientation is beyond the scope of work for me.
I think a few people in EU got a US one as part of the screen isn’t behind the bezel on that, with a view of mounting it horizontally, with buttons at right, not below. Even this doesn’t work ideal with Nxpanel, as the onscreen indicator for the hardware buttons are in the wrong place, and internal hidden UI buttons needed for making it work, are shown, so looks a bit messy. For them I can probably hide the buttons, but the indicators are still in wrong place and the display will not look cantered.
So in summary, NxPanel is really totally optimized for the EU version, because that’s what I have and use
Sorry, can’t be of more help.