Why is 'Focus Mode' not working on my iPhone 15 Pro?

I’ve had an iPhone 11 Pro and smart activation of work mode has worked flawlessly. Now I’ve changed to an iPhone 15 Pro and it won’t activate anymore. I have even set up a specific location where it should activate but it does not work either.

I have deleted my old iPhone and yes, I have restarted the phone.

[Re-Titled by Moderator]