tl;dr: Microsoft's new WebView2-based Outlook takes roughly 10 seconds to display an email when clicked from a Windows 11 notification, compared to nearly instant in Outlook Classic—and it's actually faster to ignore the notification and open the app manually. The new Outlook also runs as 10 separate processes and uses 4x the RAM of Classic, limitations inherent to its Chromium-based web wrapper architecture. A real fix likely requires a native WinUI rewrite; until then, Classic (supported until April 2029) remains the better choice for performance.