On windows with the app (not from the windows store) copy the skin folder from: c:\program files (x86)\Kodi 19\addons\skin.estuary
to: %appdata%\Kodi\addons

go to %appdata%\kodi\addons\skin.estuary\xml
(create a backup copy of home.xml)
Line 1056 on that file (on notepad click on view -> status bar) would say this:
<param name=”onclick” value=”ActivateWindow(shutdownmenu)” />
Change to:
<param name=”onclick” value=”Quit()” />

You can edit DialogButtonMenu.xml to change the options in shutdownmenu. Edit the “visible” line for options to say no. Make a copy first!

Source: Kodi 19 with estuary. Edit shutdown menu/options

Source: mb21/panwriter: Markdown editor with pandoc integration and paginated preview.