If you hate the downdraft cooler, just spend $32 on a Hyper 212 Black Edition. For the most part, all the problems from the OG hyper 212 were fixed. If you want, price match it at a big box store.
Are you running OCs daily? Your VRMs won't cause any problems as long as they're under spec thermals. Also, NAND performs better when it's a little warm anyway so I wouldn't worry about that. Just buy a Hyper 212 Evo, they're stupidly good coolers for the money.
I think the main issue with the data points you've provided is that the thermals you reference are an OC from 3.4 GHz stock to 3.8 GHz all-core. So of course in a stress-test scenario with +400 MHz all-core (which in and of itself is silly to do on Ryzen 2000+, especially for the 2600s target...
I had this same issue with Mirror's Edge on my GTX 960M a while back. The solution was to delete PHYSXCORE.dll and PHYSXDEVICE.dll from the game binaries folder and leave PHYSXEXTENSIONS.dll. The older .DLLs would collide with the new ones and cause problems, but you gotta leave the extension...
The stock Ryzen coolers are more than capable of handling a 2600. The problem seems more likely tied to voltage control. I would say disable MCE in your BIOS to start.
Another thing to note here: idle temps are really not that important whatsoever. Pay more attention to temps under load. Your...