Stuck on iCloud Security Code while installing ios upgrade

I am installing ios upgrade on my iPhone, but when it gets to the "iCloud Security Code, Enter your Security Code" screen, I'm stuck.

I don't use iCloud Keychain on any of my Apple devices and I am not interested in using it on this device. I click "Forgot Code" and have tried both options "Approve from Other Device" and "Reset iCloud Keychain", but neither option progresses past the step. No matter what I try, I return to the "iCloud Security Code, Enter your Security Code" screen. My device is stuck.

Help?!?!?!?