[ubuntu] Display/monitor - go 4K or 2K

Hi all,

I'm prepared to upgrade my 24" Samsung monitor/display, 1920x1080, which has been ruing several years. I shall use the display for daily office work, no gaming nor graphic editing. My option is 27" display but wonder whether go 4K or 2K. For color I prefer 4K but the fonts will be too small to read documents and web browsing. I have no pre-set budget.

Please give me some advice for its selection. Thanks in advance.