Check that both monitors are running the same resolution.
Also run "xdpyinfo" (rpm is xdpyinfo if you don't have it installed, I don't know if this tool works on wayland or not) and see if the listed size of the screens and dpi is similar on both monitors. I have seen some devices that the EDID info is wrong and because of that it calculates the DPI wrong and adjusts sizes based on that data. MIne produces output like this:
Screen #0:
dimensions: 3840x2160 pixels (1016x571 millimeters)
resolution: 96x96 dots per inch
Mine is actually 940mm x 530mm so EDID lists my monitor as about 8% bigger than it really is
Windows may have a monitor device table that it uses that has correct values in it, or windows 7 may not be playing any DPI scaling games.