How to resolve 'Sign out is not available due to restrictions' on Apple ID across devices?

I cannot sign out of my Apple ID on any device. I have two iPhones, older one is on iOS 18.4.1, new one on iOS 26.1. Tried sign off on old one, it is restricted, to find out that it is the same situation with new one.

Screen Time and Stolen Device Protection are off.

The message says ‘Sign out is not available due to restrictions’.

I do not have wrong login attempts, nor changed ID details or similar.

Can you help?

I read that I may need "Account-level security lock cleared"

[Re-Titled by Moderator]

Original Title: I cannot sign out of my Apple ID on any device. The message says ‘Sign out is not available due to restrictions’.