I very-dislike this compact user display "list" of one. There are three users. I would like the lockscreen to show three users simultaneously without hovering in any particular place.
How do I restore the functionality ?
I checked in System Settings - Users and Groups as well as the Lock Screen settings for macOS Sonoma. You can choose whether the display the login screen as input boxes for the user name and password (no icons/avatars) or instead use the default user icon display, but I see no option for auto-expanding the icons to show all the users simultaneously, without hovering over the user icon stack first.
There is an option in User and Groups to create groups. I wonder: if you create a group for each user and just assign one user per group, will they display as separate icons? You could try this, and see if it approximates the behavior you prefer. (I have no objections to the existing hover method of showing the icons—it doesn't bother me at all, but everyone has their own tastes.)