I’d like to note that since that I’ve updated to tweaked the hell out of my project settings regarding how lighting is handled, studio drivers, rebooted, and I’ve had 0 GPU-related crashes since then (without -d3ddebug). Thing is, order independent transparency is off now, so that is a problem.
Thing I noticed with -d3ddebug is that at times (especially when anything transparent was being rendered, so just looking in the general direction of transparent objects even when obscured by walls) my message log would be obliterated by spammy error messages, so I presume that d3ddebug prevents the crash altogether before it can happen by detecting the issue. So all I’ve really learned to confirm with this was that it is indeed something transparency related (though that part was already hinted at by the crash logs, but GPU stack dumps could’ve been unreliable). The avenue seems mostly unexplored as googling the messages brought up nothing even close to what I saw, so maybe getting the info to Epic could result in some fixes.
So unfortunately, it is most likely that order independent transparency is currently not stable enough to rely on.