Код:

<?xml version="1.0" encoding="UTF-8"?>

<PROPERTIES>
...
  <VALUE name="ui::main_window">
    <ui::main_window width="1910" height="995" full_screen="0"/>
  </VALUE>
...
</PROPERTIES>

Код:

File = %A_AppData%\Steinberg\Cubase 12_64\UserPreferences.xml

FileSetAttrib, -RASHNOT, %File%

$oXML := ComObjCreate("Msxml2.DOMDocument.3.0")
$oXML.Load(File)

$oAll := $oXML.SelectNodes("//member/int[@name='surface.system.focus']")

For $oEl In $oAll
    $oEl.SetAttribute("value","-208384")

$oAll := $oXML.SelectNodes("//member/int[@name='surface.system.root']")

For $oEl In $oAll
    $oEl.SetAttribute("value","-13679270")

$oXML.Save(File)