I'm certain I've got an installer for the older X4 windows version saved on my PC, runs happily on Windows 10. Not got access to it today sorry, but I can check tomorrow.
I think this is the link to the relevant bits, it's got the command line interface for mac there as well (Helpfully in 'Archive' rather than 'Legacy').
I thought that Wall Designer was supposed to support X4 if the firmware was up to date but I may be wrong. I actually preferred the old interface to the new Wall Designer.
[edit: sorry, I've read your post properly now and see you had this link already.]