You'd be better off going up to a 2080 Ti if you really need to upgrade.
not worth it, since the gain is not significant enough. What is the rest of of your computer? Is another component holding your GPU back?
I'd say your 4770k is already holding back the 2080, it will only be worse if you upgrade the video card further.
I'm not entirely confident in this site, but it says you have a 38% bottleneck currently: https://pc-builds.com/calculator/Core_i7-4770K/GeForce_RTX_2080/0uX12llu/8/
My personal estimate would be more around 20%, but that's still more to gain than you would get from upgrading to a 2080 Super or 2080 Ti.