7th gen. Nothing wrong with an i7-7700k paired with a GTX1080 or RTX2070. If you want SLI 1070Ti, just go out and get a 2080Ti.
I've had that combo for years, and if your goal is 2560x1440 or 3440x1440 then it can do a reasonable frame rate at the highest of settings.
If you are after huge FPS numbers at low resolution, the 7700 or 7700k will do within about 10% of an i7-8700k or the i7-9700k.