Is the EX321UX worth it over a standard 4K gaming monitor?

Its Mini LED backlight with local dimming gives much deeper blacks and brighter highlights than edge-lit 4K monitors. If you want HDR that actually looks like HDR, it is the step up; if you only play SDR, a cheaper 4K panel covers the basics.

How does it compare with an OLED gaming monitor?

OLED wins on per-pixel contrast and motion clarity. The EX321UX wins on full-screen brightness and carries no burn-in risk, which matters if the screen also shows static desktop windows for hours.

What do I need to drive 4K on this monitor?

A recent mid-range or better graphics card for 4K at high frame rates, and a DisplayPort or HDMI 2.1 connection for 4K at high refresh. Console owners should check their console supports 4K output at the refresh rate they want.

Does it work for office work as well as gaming?

Yes. The 32-inch 4K panel gives plenty of desktop space and sharp text, and the size suits side-by-side windows. It is a large, heavy monitor, so check your desk depth and stand.