Overnight update to iOS 15.6 bricked phone into continuous boot loop and Unexpected Error 2015

An overnight update of my iPhone 11 Pro Max to iOS 15.6 bricked my phone into a continuous boot loop, force update gave an unexpected 2015 error, which there are no help articles about, there is not option to roll back to iOS 15.5, the backup on my computer had the Advisor unable to tell me which folder was the last updated and when it was updated. In the Genius Bar they were not able to update. It's not possible to see the last update dates unless you have a phone able to unlock and not currently bricked.

I'm stuck with no informed consent for restore as I have no way of verifying when that was right now. I would also like to roll back to 15.5, although a lot of the AI enabled search functionality has become almost useless.

What to be done?