Quads were done long ago. Far Cry4, Gta5, Doom 2016, Ghost Recon to name few I've tested ran much better with hyperthreading on my 2600k at 4.5 with 1080Ti in 1440p. Work load in these games were maxing the cpu with HT off. It caused fps drops and stutters.
9700k is ok but it's usage is already maxed out in high end games now, much like 8600k/9600k was already since release.
I would not go a hyperthreadedless cpu today going into the future in gaming. 6/12 thread cpu minimum, 9700k despite being 8 cores falls short of that. Intel went HT for a reason, that's to complete with Amd since they offered SMT on majority of their processor's which is becoming more and more beneficial in games.
Imo, 10th/11th i5 model will do you more favours now and later compared to 9700k would. If go to compare, don't look at maximum fps margins, that won't say much when you're actually gaming. Ya need to look for 1% lows, but even then, cpu usage isn't really gauged in percentages. For that, searching 9700k high cpu usage would give you user feedback results. A tapped out cpu isn't good for performance. Of course, this depends on game, which accounts most triple A titles of recent and I'd imagine upcoming as well.