It appears you are susceptible to noticing the difference in pixel density, likely made worse because you are switching between the PC and Xbox.
Quite simply, the Xbox is running games in 720p at best, upscaled 360p at worst. The monitor is 1080p and physically large, so the lower resolution is made apparent by the fact that the pixels are literally larger and there are more physical pixels making up a larger "virtual" pixel. Hence why it appears to be fuzzy.
The PC is likely running at 1080p, so you dont get that effect.
Switching to a smaller or lower resolution monitor might help.
TL;DR
Consoles be weak, cant drive pixels like a proper PC can 😛.