This was my nightmare, but...
Hey everyone! Started playing 5 days ago and ran into these DirectX11 crashes. But!!! I did a few things and they stopped (already two days with out crashes with ~6 hour sessions). Maybe to someone it will be useful:
-installed Microsoft Visual C++;
-updated the BIOS to the latest version for my Asus motherboard (2020/09/21 Release);
-set full-prefomance mode in NVidia Control Pannel->3D Settings->Global parameters ->Power managment;
-also in 3D Settings for ffxiv14_dx11.exe I have set V-Sinc in Fast-mode and fps to 120 (but in game I still have 140~144 lol);
Sorry for my bad English. Wish you, folks, to find your own effective solution of this trouble.