Browsing through some old threads going back to 2015 (DX9) One thing people have had success was switching to the last old graphics drivers. I know Nvidia pumps out a lot of updates. It is worth uninstalling and going back one. Another thing were some overlays like Geforce Experience, were causing some issues. (questionable imo) The sad part is Square enix does not really have a dedicated tech support. This issue has been going on for years. I bet anything this is a driver issue more specifically something that was updated.

First thing I would do is remove any graphics apps like geforce experience completely. and reinstall the last driver you were playing on. Some people may have auto updates on.