Using Classic Outlook on Windows for personal email, calendar, and contact management
Since you are using New Outlook, you could add your Gmail account to New Outlook and that should natively sync the calendar. It should work better than the Internet Calendar. Edits you make in New Outlook or Gmail should sync both ways too. This is capability that is only in New Outlook. This does not work in Classic Outlook, and you would have to use Internet Calendar with it.