Early adopters of 4K monitors often struggled to read small text. That’s because many older applications were programmed such that interface elements have a defined, concrete size in pixels. The higher a display’s resolution, the smaller the interface appears.  Thankfully, this problem is mostly solved. Windows and MacOS have excellent text scaling options and most software developers have updated their applications to properly support 4K displays. It’s still a problem with very old apps that were never updated but, in general, it’s rare to see tiny, unreadable text on a 4K monitor.