Inclined to think it's GPU but this is weird.
So I came across a reddit post where someone said reseating (removing then reinstalling) the GPU solved his crashing issues, but the problems would come back about 2 months later (source:
https://www.reddit.com/r/techsupport/comments/1r41awh/my_gpu_seems_to_have_crash_sprees_every_couple_of/)
Got me to think that actually I had to take out my GPU as well for Zotac CS and it worked for a while afterwards.
So I reseated my GPU and D2R and other games run fine again.
Someone said it might be GPU sag, but not 100% sure. My case is a Hyte Y60 with cable riser so the card actually stands vertically up. I don't notice any GPU sag on the floor of the case that the GPU sits on.
I have a feeling the crashes would come back again eventually.
Would this still be a GPU issue then?