The game crashes because your motherboard is not applying the required core voltage to your processor.
Solution:
+ To increase the core voltage manually with the BIOS.
+ Manually lowering the CPU multiplier with the BIOS.
+ Replacing the motherboard with going a computer store.
If you are doing an OC to your processor, you must apply the stable CPU core voltage value according to the VRM quality of your processor and motherboard. If you are not doing, you should also apply it because your system is not stable with the factory settings.
Goodluck...
Yeah I'd definitely prefer not to overclock this CPU, but I'd like to underclock it even less lol! Even if I had a cheaper chip I'd feel the same way, it should be able to maintain stock speeds at stock voltages. I still hope to try my chip in a different mobo and/or a different chip in my mobo (and maybe wait for another BIOS update) before starting any RMA.
I'd just like to thank you mstfbsrn980 for trying to recommend potential solutions, or at least workarounds 
I've read a lot of forum posts about similar issues in these last few days, and your recommendations are pretty consistent with most of the good advice I've seen on the subject.
I missed your reply here but you asked a really good question so I wanted to answer.
"How easy is it to duplicate this issue?"
For me, it isn't easy to duplicate this issue as it just seems random, and it isn't only in Marvel's Avengers (but it is easiest to provoke with that title for me). It's a pretty new game that apparently has some Intel-specific optimizations, so encountering issues with that application most frequently led me to do some more rigorous stability testing with what I hoped were the relevant instruction sets in Prime95. The issues don't persist in Prime95 though, and if it were because the game supports AVX-512 or something then you'd think all Ryzen chips would have similar issues but they don't. Before installing this game, problems happened very infrequently and seemingly at random, still doesn't happen very often at all. I had probably seen the issue in Blender most often before, which I believe uses AVX2 instructions. Of course I can understand if they are still working out some kinks when it comes to supporting some formerly Intel-specific instruction sets, I just want to make sure my CPU is alright.
Being that I am gaming at all, I certainly don't want to run a gimped setup if I don't have to lol! I get what you're saying about doing it to diagnose, but I've already diagnosed more than any end-user should have to. I'm sure you wouldn't call gimping the setup a fix either, no one should have to run at below stock clocks on a pristine CPU as a workaround. My plan is to see if the next BIOS update will fix it, and I'm hopeful since it's still a pretty recently released chipset. I'd also like to get my hands on a different motherboard (just in case) to see if the issue persists that way, but if everything else fails I will probably start an RMA for the CPU. Since the OP had a basically identical issue from what I gathered, I'd suggest that they try to RMA their CPU too if this BIOS update doesn't end up fixing the issue. Their most recent edit says they've had no issues since updating their BIOS though, so even though it was a really intermittent issue that is some reason to be hopeful 
For the specs...
CPU: R9 3950x
GPU: Sapphire Nitro+ 5700 XT
Mobo: B550 Taichi (AsRock)
RAM: G.Skill Flare X 3200/c14
PSU: EVGA 1200w P2
Give 43 multiplier to the CPU core ratio with the BIOS.
Give 1.45 manual voltage to the CPU core voltage with the BIOS.
Your BIOS may be trying to turbo your processor more than the normal. This could be due to any changes you made with the BIOS. It is necessary to examine in great detail.
