Hello,
Unfortunately there is no granular setting for the Power button on the CTRL-ALT-DEL screen. Either is enabled or disabled using:
1.Press Win + R to open the Run command dialog box.
2.Type gpedit.msc and press Enter to open the Local Group Policy Editor.
3.Navigate to User Configuration > Administrative Templates > Start Menu and Taskbar.
4.Double-click on the Remove and prevent access to the Shut Down, Restart, Sleep, and Hibernate commands option.
Other option is to keep the button disable its functionality by changing the next registry chain:
[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer]
"NoClose"=dword:00000001
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