The benchmarks I've reviewed/studied do not yet show the 6c/6t CPUs taking a discernible hit on minimum FPS....but, I doubt those reviewers are running any sort of chat and streaming applications as well in their comparisons, and, perhaps they should. (If you've already got the 300-series mainboard and are semi-committed to an Intel solution, I'd start my shopping with the 9700K/KF, if the 9900K/KF is out of reach.)
If you don't yet have a mainboard, the B450 and R5-3600 or R7-3700X are among the immensely popular pairings these days.
With current prices, even the R9-3900X-based rig could be assembled for tad less than one built around a 9700K, which although $20 less than the 3900X (now available as low as $420?!), the 9700K...