Current script:
$ShortcutPath = "$Home\Downloads\Extend Screen.lnk"
$IconLocation = "C:\Windows\System32\DisplaySwitch.exe"
$IconArrayIndex = 6
$WshShell = New-Object -comObject WScript.Shell
$Shortcut = $WshShell.CreateShortcut($ShortcutPath)
$path = "%windir%\System32\DisplaySwitch.exe /extend".Trim('"')
$Shortcut.TargetPath = $path
$Shortcut.IconLocation = "$IconLocation, $IconArrayIndex"
$Shortcut.Save()
Result: