I personally wouldn't worry about it your CPU is roughly equivalent to i3 8300, which is not bad as far as gaming goes, that being said not sure a 2070 RTX is worth the cost at this point it probably a better buy to with a 1070 TI and save your money.
My motherboard is a GIGABYTE Z170X-GAMING 3 and can support up to an i7 7700k, which I can get a good price on $150 off sale... Would I get quite a longer lifespan if I upgraded my 6600k to a 7700k?
Looks like the jump from a 1060 to 1070 is much larger than the jump from 1070 to 2070 other than in multi rendering. Plus I heard the ray tracing is pretty much useless on the 2070 and thanks fps. and looks like its much more happy with my 6600k making the 7700k a nice option to consider but not not as big a deal.