SUMMARY
If you have a Lock/Logout widget and configure it to only show that button, clicking on it will only show "Shut Down Now" and "Cancel". There is no way to, for example, restart, unless you configure this widget to display, in that case, "Restart" *and* click that button. You are locked to only be able to "Perform Action Now", where that Action is the button you pressed. For Lock/Logout, the user might only have one button configured so as to not pollute the panel, and to simply have this as a "catch all" to display session options.

The action can be selected from KRunner by searching for, say, "Restart", but the "Desktop Sessions" category may not be the first result or the options could have jumped around and changed by the time a user presses enter.

This may be intentional, as if you do this from something like the Application Dashboard where the buttons are bigger, and the action is less generic than it is with the Lock/Logout widget. Although I still think in that case it should be customisable what options display on that screen, to restore the previous behaviour.

Alternatively, a widget that can act as a button to show any number of options as a replacement would also work.

STEPS TO REPRODUCE
1. Add Lock/Logout Widget
2. Configure it to only display "Power Off"
3. Click on the Widget
4. It does not display the other session management options, it acts like the button on the Application Dashboard/Launcher/Menu, or the option from KRunner. This is unexpected behaviour from previous Plasma versions where you would see a list of session management options, and I believe there was an option for this setting to take effect immediately.

OBSERVED RESULT
Session management screen only displays the option to perform the action you pressed immediately or to cancel. There is no way to show all session management options (Restart,  Poweroff, etc). This is a significant change in behaviour from Plasma 6.0.5 and below, where you could see all management options, so when using the Lock/Logout widget you could press the "Poweroff" looking button and then choose whether you wanted to logout, restart, poweroff, etc, without having to do so from any other screen.

EXPECTED RESULT
The options in the Application Dashboard/Launcher/Menu could, by default, have this behaviour, but Lock/Logout should at least have an option to configure it to display all session management options with a single button press. I assume Lock/Logout is using the same pattern as the Application Dashboard/Launcher/Menu.

There is an option in Power Management to "Show logout screen" on actions such as when the Power Button is pressed. There should be a way to enable this for whenever a session management button is pressed, both from Lock/Logout and if the logic is indeed shared then also in the Application Dashboard/Launcher/Menu.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.9.5 Linux Zen
KDE Plasma Version: 6.1.0
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.1

ADDITIONAL INFORMATION
I am using the Wayland session, but I don't think this is specific to X11 or Wayland.