Four thoughts.

1. It sounds like you may be overheating? That will cause issues somewhat randomly.

2. You have done a lot on the graphics side. Many people don't realize that DX11 also controls the audio. Is there an issue with audio drivers/system?

3. Finally, from the software list I see many ASUS system apps. Is one of them causing issues? i.e. are power manager settings or other settings at fault?

C:\Program Files (x86)\ASUS\AEGIS II\AEGIS_II_AlertService.exe 00001AF4

C:\Program Files (x86)\ASUS\AEGIS II\Boost Launcher\BLMonitor.exe 00001D04
C:\Program Files (x86)\ASUS\AEGIS II\Lighting\AudioDetect.exe 00001D0C
C:\Program Files (x86)\ASUS\AEGIS II\Lighting\CheckCD_RomLighting.exe 00001CE8
C:\Program Files (x86)\ASUS\ASUS Manager\Ai Charger II\Ai_ChargerII_TrayIcon(ASUS_Manager).exe 000003C4
C:\Program Files (x86)\ASUS\ASUS Manager\AsHKService.exe 00000FEC
C:\Program Files (x86)\ASUS\ASUS Manager\PC Cleanup\SecureDeleteBackground.exe 00001D84
C:\Program Files (x86)\ASUS\ASUS Manager\Power Manager\Power Manager_background.exe 00001884

4. Once upon a time I was having random crashes in FFXIV. The root cause was when I plugged in my my cell phone to charge it would draw just enough current , when graphics where going full bore, to pull down the power supply and reboot the system.