Outlook Classic is a beast. It has over 20 years of development. New Outlook is a giant shift away from being a traditional email client that downloads mail offline to your PC and syncs changes to the server, to being cloud first.
With the New Outlook, it is basically just the Outlook website, and Microsoft is working hard at bringing offline functionality back to the app. It will take time, but they've come a long way so far and the 2025 roadmap has lots more features coming. For example I tried using the New Outlook a year ago and hated it, but now it's pretty good. I only have to switch to Outlook Classic to do Mail Merges now. (Mail Merge is coming to new Outlook this year).
