If I understand your request correctly I think you want to have your project open the same as when you last saved and closed it. If that is what you want, take a look at the Cubase File>Preferences>General menu. In that menu you will find a dropdown named “Open Projects in Last View Used”. Choose the option “Always” from the dropdown.
This option may help you but, the available options don’t work like I think they should. That’s why this feature request (and many other similar ones) are posted.
Regards 