It often is. If I am limited by the GPU I get about 35 FPS @ 4K.
Most of the time I get less and limited by the main thread. The 2080 not 4K capable how do you mean? The 1080 Ti was called 4K capable when it came out and nothing better existed 
I depends on what FPS you are willing to put up with.
Most games run at more than 60 FPS for me.