No single GPU will run 4K at 60fps in today's games. You're basically looking at a 780 Ti SLI setup, which would be $1400 in video cards alone.
I don't think 1080p looks blurry, but games are certainly much more vibrant at 1440p+.
Intel i7-8086k @ 5.1 GHz | Asus Maximus X Hero | 32GB Ballistix Sport LT 2400Mhz RAM | Nvidia RTX 2080 Ti