Microsoft's new Outlook takes 10 seconds to do what Outlook Classic does instantly on Windows
(www.windowslatest.com)
The "traditional" Outlook (Which Microsoft now calls Outlook "Legacy") stores your data locally, on your local storage inside your PC.
"New" Outlook allows outlook.com to sync your mail to THEIR MAIL SERVER, allowing them to train the AI on it, etc. It's no longer YOUR email. It's theirs.