E.g. here's benchmark numbers delivered by Nvidia, and even their best card doesn't hit 120 fps in all games at 4k - if you want fps over resolution, you're going to switch down, especially if you aren't on a truly top-of-line card. https://videocardz.com/77983/nvidia-geforce-rtx-2080-ti-and-...

These benchmarks are conducted on the games "ultra" settings, which most of the time forgo any idea of resource efficiency. Games are highly configurable and often give the options to increase framerate a lot at a negligible visual impact, even just lowering the preset to "high" achieves this most of the time.

Also, with variable refresh rate, reaching exactly the maximum refresh rate of the monitor isn't very important.

The comment chain also referred to reaching "more than 60 frames on higher than 1080p resolution", there are luckily more options than 4K.