Microsoft Defender and Battlenet issues - BLZBNTBGS80000011

So, I've been going round and round with Blizzard support on an issue with my Windows system. It's a centrally managed system running Windows 10 and Microsoft Defender. I have a local administrator account and can do most things, but I can't add Defender exclusions, so I am at the mercy of Blizzard support to try to figure this out. So far, I am on the 3-4 message and here are the current suggestions.

Reinstalling the client:

https://battle.net/support/article/34721

https://battle.net/support/article/34719

Background Apps:

https://battle.net/support/article/23848

New Admin Account:

https://battle.net/support/article/34550

Upload new information files:

https://battle.net/support/article/12988

After the initial response, they requested some general information about the system and being the support person that I am, I was glad to comply:

https://battle.net/support/en/article/12988

Overall, the support experience had been very helpful, and the representatives have been very kind and patient. It initially took some time to get a response (I started this adventure during the holidays) but they have been very responsive since then. I'm also grateful I have an M1 Mac that runs the game just fine while I figure this out.