Imac is opening without a password - even though it is set to require a password

I'm really worried, because my iMac suddenly doesn't require a password.

Just turning on the iMac enables anyone to access all my files, e mails, everything. Clearly a disastrous situation from a security perspective.

I have iMac Retina 5K, 17-inch, 2019, with Ventura 13.0.1 software.

In System Settings, Lock Screen, I have the following -

And in System Settings / Login Password I have

But when I turn off my iMac and turn it back on again, everything opens without needing any password at all.

How do I make my iMac require a password? I really want it protected!