I believe I have found a bug related to FFXIV DX11 and use of Radeon GPUs. I can only specifically speak for the 6900 xt installted in my PC.
This will be a lengthy post as I explain all troubleshooting steps and the issue I've seen.
The issue / crash behavior is a complete power off of the desktop without any error messages. Game does not crash to desktop. There is no blue screen. There is no windows event log to correlate with the crash. It is a complete and total power off as if the plug was abruptly pulled from the wall.
Common causes of the described issue are: overheating, power supply issues, virus, and bad memory.
I have ruled out all of the above with a large selection of stress tests, other game benchmarks / game time, a fresh windows 10 install, DDU Radeon Driver install, fresh FFXIV install, and a brand new 1000w PSU that did not change the crash I am seeing.
The crash occurs in raid, and loading into housing instances from what I have seen. Most commonly can be replicated by repeatedly entering and exiting a house in a ward (tested with a Large FC house). With my setup the crash can *easily* be replicated while using the display preset settings of "Maximum". This will almost always crash on entry into a house or mid raid in current Endwalker EX trials.
Setting FFXIV to "Standard Laptop" seems (based on 3 hours of testing) to resolve the issue as I have yet to replicate the crash with low graphical presets in FFXIV. This to me indicates a problem with FFXIV DX11 implementation and Radon Drivers for some setting in the FFXIV graphical menu.
That being said it is very important to note that this crash is SPECIFIC to FFXIV. I have tried and failed to crash my computer via any other title that uses DX11 or any other stress / high power usage scenario. This includes strenuous testing such as running prime95 CPU stress while launching and loading other DX11 titles. Playing other DX11 titles on maximum settings for extended periods of time, etc.
Finally, these issues began with the release of Endwalker. This PC has been in service since June 2021 and never one exhibited these problems in Shadowbringers. On moving to Endwalker no settings were changed on my FFXIV System configuration but these hard crashes began. Others I know with similar setups to mine who use NVidia branded 30 series cards do not have similar issues and cannot replicate what I am seeing.
Please Square, look into this as compute components are next to impossible to get and they are very expensive. Additionally crashing without warning and being thrown into 2 hours in queue right before savage makes this game almost unplayable due to this issue.