The BIOS update is the ultimate solution here, will ensure maximum compatibility with your Ryzen 5 and will benefit you outside of Vermintide 2 also. If you’d rather not update your BIOS, I’m happy to contact Steam and request that they issue you a refund.
Sorry to hear that. I don’t think updating the BIOS is too “out there”, it’s evident there’s some sort of rampant incompatibility between the Ryzens and some motherboards that requires a BIOS update. I recommend this because it’s proven to work successfully for many, many players with improvements outside of Vermintide 2 also. 
Ultimately there will be an underlying explanation for your PC crashing outside of Vermintide 2 itself, most likely hardware-related. I was hoping the BIOS could be the one-shot panacea that has worked for so many but in your case it’s likely to be a process of elimination.
I wish I could solve this immediately for you but that won’t be possible. You’ll want to check your overclocks, check for overheating, run the Windows System File Checker, etc. More information here: [PC] How to Resolve PC Crashes, Loss of Responsiveness or Blue Screens (BSOD) – Fatshark
devtrackers.gg