So you are looking at @ $700± to accomplish what? A few more fps? At 1080p, yes, that's @ 10-40ish fps depending on the game. At 1440p it's closer to 10-20fps and at 4k there's little to no difference.
Now if you were doing production work, compression, encoding, decompression etc then I'd put a good value on it, the 12700k is just under 2x faster, and when time is money, that's going to pay for itself in a few days.
Then there's the ddr5 debate. With your current ddr4 reused, those fps/times aren't going to change. With ddr5 and possible future upgrades, they could. But ddr5 really isn't worth the cost in ram or mobo atm.
The 12600k fps/times are not all that much worse than the 12700k, and the price tag is much more appealing, but that's still $500 for gains you'll not see much of with a 2070Super.
If I had to choose, the 12600k by a landslide. While it's production values aren't as good as the 12700k by a fair margin, for gaming purposes there's little difference.
But personally, I'd be saving that cash for a better gpu/monitor.