Ok, my opinion. I would either go with the 9700k because it runs cooler AND because will all of the hyperthreading vulnerability mitigations that have already, and are continuing to be, found and patched, the hyperthreads offer less and less for your dollar every day. The upcoming models are, tentatively, seemingly all hyperthreaded models. Unless you are willing to wait, because more cores, and disable the hyperthreads, which seems like a double waste because you'll be paying for them and then disabling them, then I'd recommend sticking to non-hyperthreaded models. Yes, you will still get SOME extra performance from the additional hyperthreads, but to be honest if it's a gaming machine you will probably never notice the difference translated into more FPS anyhow.
Or, completely change camps and go with an 8/16 Ryzen build, since AMD has only a few vulnerabilities and no performance hit to speak of, and it's been a long time since anything new that was said to affect Ryzen has been discovered. Plus, at the stock configuration the Ryzen processors have much better performance per dollar anyhow.
If you are deadset on Intel, then I'd just go with the 9700k unless you are willing to wait for a ten or twelve core model OR if you are willing to pay for gimped hyperthreads because you actually need that extra bit of work, then that's fine too. I would not pay for a 9900k or KS right now though. I think that is a poor decision when there are higher core count parts coming before too long. Really depends on how badly you need this now.
What is your current configuration?
What is wrong with it?