Currently the Lock Screen Windows spotlight is truly broken, and it has nothing to do with your account.
I've done a clean install of the latest "Public Release" build 22631.3155 and created a local account with all the default settings. The only thing I have done was to activate Windows with a digital license so I could access personalization. Background Windows spotlight works just fine, and a new batch of four images has appeared after about a day. Lock Screen Windows spotlight shows the default image and the calendar. That's it.
It doesn't work out of the box. I just wanted to tell you not to burden yourself with this. It's broken.
Then I've downloaded a virtual machine of the Windows 11 development environment. It is a "Public Release" build 22621.3007 of Windows 11 Enterprise Evaluation edition, version 22H2 from January 2024. Lock Screen Windows spotlight works just fine on this virtual machine!
TLDR: It used to work, but currently it's broken.