In the local guixt.ini, we use a "SwitchTo" to a system-specific guixt.ini file (&database in file name). In these system specific guixt.ini files, we use the commands:

StartMinimized Yes // Start with a minimized window
StartHidden Yes // Start with a hidden window

But they have no effect, so what should we do?

Please use these commands in your local guixt.ini, before the "SwitchTo" command.