In my case, it's not antivirus, unless it's Windows Defender. I have a very clean computer, when it comes to installed programs, and I don't run 3rd party antivirus programs. I don't set programs to auto-update or notify me of things, so when they're closed, they're closed. I'm familiar with task manager so I can see if there's oddball stuff running in the background - there isn't. My system tray is kept barren (only "safely remove USB devices" and the Windows Defender shield), and my background processes are entirely clean (normal, common Windows features are running).
Logitech G-Hub is the exception in my case - it's always running, per my preference, but if I disable it and play, I still get the black screen / memory spike / required forced exit perhaps 10% of the time. I see no behavioral difference between having G-Hub enabled and having it disabled. It's perhaps 1-in-10 times for me; logging in and out four or five times a day, I end up seeing the black screen and needing to force exit about once every other day.
Just to note, I honestly don't care about the bug, it takes three seconds to resolve and it doesn't happen after every play session. I'm just here to kick in my two cents, hopefully to help those for whom the problem is a larger issue.
That being said, I've added the entire FFXIV installation as an exclusion in Windows Defender, so I'll see if that makes a difference, and report back soon.
Good luck all!