so your
Asus Rog Swift PG258Q monitor uses 100x100mm Vesa compatibility do you want to drill a hole and mount it through your desk or you are looking for a clamp on edge of desk solution ? do you have picture of your desk, and where you intend to mount it on (is the back on it preventing clamp mount ? etc etc...) or do you just want a vesa that is free standing on your desk? not that I would understand why you would not just use the monitor stand at that point.