Game crashes with black screen on login, no error message

[Basteala]

Per technical support staff in other topics, I am putting this in a separate topic here.

After logging into the game and getting past the queue, I get a black screen, the PC goes into standby for 3-5 seconds, then returns to the desktop. Now originally I thought this was related to heat, as many online have suggested for other people, but here's two reasons why I DON'T think that is the case:

Firstly, I attempted to use the game on a different PC with lower performance settings, and it too had this unusual crash. More frequently, I might add. This PC had also not been used in any way, shape or form for a couple of days, and it is fairly cold in terms of weather at 54 degrees with no heat on.

Secondly, the PC isn't turning off, nor is it rebooting. Instead, after the screen comes back from its darkened status, everything is back to how it was: the browser is up with it respective tabs with no load time, Final Fantasy is up, but it is back to the start screen, any other apps are likewise running, not starting up as they would be with a PC crash. There is no smell of ozone which is another symptom of heat related damage to a device.

* Both PCs use Windows 10 and are currently up to date
* Both PCs are using the Windows PC (non Steam) version of the game
* Both PCs are on a WIFI connection protocol 802.11ac
* the PC crashing more has a SSD, GeForce 1660 Ti, and 16 GB ram
* The PC that only very occasionally has this issue has SSD, GeForce 3080, and 32 GB RAM

- I have attempted multiple devices to eliminate the risk of hardware failure
- I have updated AND rolled back both display drivers
- I have lowered the settings of the graphics in case these were too intensive
- I have attempted to launch with and without Directx11
- These issues first manifested late last week, around 06.03.2021

Originally this issue was isolated to my main toon, Basteala. In fact, I had even logged into my alt without incident, then swapped to my main in an effort to flush the cache and force a fresh character data load. This worked for a time.

I exited the game, and logged back in to see if the solution was sustainable. However, my main character crashed almost immediately. I switched back to my alt, but now she was crashing.

I attempted to login via a different world server, both to try and change the zone, and the server, to see if either of those had anything to do with the issue. Despite successfully logging into Ul'dah, the game crashed upon loading. I tried a third alt, and they too immediately crashed.

Currently this issue is persisting on the older PC. The newer one was able to successfully login onto the other server and I have it running overnight for further data collection.