Outlook is what is keeping me away from Linux Desktop.
In general, unless you need advanced Excel features, you can switch to linux.
[0] e.g. https://www.neowin.net/news/microsoft-cant-help-break-window... and couple others
While email is asynchronous and I can live with not seeing it all the time (I check it occasionally anyway), the calendar feature is a must, and specifically the reminders. This is why I cannot live without Outlook launched, and it reminds me of meetings I would miss otherwise.
Or maybe you're talking about needing Exchange integration? I don't know what the state of that is on Linux these days.
The integration to Exchange is key as well, I need to have access to rooms, PSTs etc.
It is the poster child for enshittification.