This topic is stretched over so many threads that I felt the need to make a new one.
Wallpapers in secondary profiles seem to take on the aspect ratio of the home screen of the owner account. If the aspect ratios of the owner home wallpaper is the same as secondary home and lock screen wallpapers, there is no issue. Live wallpapers probably won't work, mine didn't.
Incidentally, if you set wallpapers with Fossify Gallery, it crops them to the shape of your screen.
Other threads have recommendations to use one of several wallpaper apps, but those crash on reboots for me.