Hi,
5DSR FF 50MP pixel size: ~41.um
X-T2 APS-C 24MP pixel size: ~3.8um
So if the lens on the X-T2 is very good, theoretically, it can out resolve the 5DSR, but practically, I don't think you'll see any difference... it'll depend on lens, shooting condition and image processing method.
Anyway, from the images the website provided, I don't see any significant difference.
Have a nice day.