That's a tough one - with Zen 3 literally on the horizon and already owning a very capable CPU for gaming.
I'm guessing the uncertainty of the 'physical' release date, after paper launch has you concerned - and perhaps stock levels on release? I've read as early as mid/late October and as late as end of November for physical launch - but that stock coupled with demand wont be an issue (but all speculation - and we've all been here before).
But, for me, i keep coming back to your 4790K - even now i look at it and see a mighty CPU. And, yes, you will see extra FPS but more noticeably you will feel the difference/smoothness when gaming with a 3600 - that is greater than the FPS improvement indicates. That said, i'm not sure it's worth the financial hit for a couple of months use - at least not for me.
Six months ago i moved 2 systems from a 2600K and a 4790K - to a 3600 and 4700X respectively - didn't change GPU (1660Ti and 1070) in either as waiting for 30 series/Big Navi - and gaming FPS gains were reasonable (depending on game) but the main difference was smoothness within gameplay and the system speed as a whole. Totally worth it for my 6/8 months use - but for 2 months, with hindsight, i would have waited if it meant a zen 3 with ~15% IPC improvement - especially with the 4790K system. (Note - i have 1440p monitors - so not an apples to apples comparison if you have 1080p)
But, I appreciate your impatience given vagueness of 'physical' release date - and possible uncertainty the 3080 may have caused with nuts demand and use of bots. Although, not expected with Zen 3 - but again who knows for sure.
*And you can get Crucial Ballistix 3600MHz micron Rev E ~£65 - great timings.
