This is the closest "official" feel. It opens Gmail in its own window without browser tabs or an address bar. Go to mail.google.com and sign in. Click the three dots (top-right).
– You can install Gmail as a standalone app via Edge or Chrome in under 30 seconds. It gives you: gmail windows desktop app
– These add unified inbox, calendar, contacts, and even Google Meet in one window. However, they often require a subscription. This is the closest "official" feel