I recently moved to Outlook because of many missing features in Mail and sync issues with Exchange and Apple Calendar (my devices were never in sync!).
So far, I’ve been really happy. I can finally trust all my devices as the calendar is always in sync, the interface is faster than Mail, especially when updating the Inbox, and I can book rooms and view the availability of my colleagues when scheduling meetings. All these things were not possible with stock apps.
I’ve also been pleasantly surprised with the rich ecosystem of add-ons - these have great integrations with Zoom, Dropbox, and many other services.
I also find the search is much more reliable than Mail.