Comment by aetherspawn

Apple suite (Pages, Numbers etc) works well, has good mobility to mobile, and is free.

Apple Mail and Apple Calendar are fine to replace Exchange, as is Thunderbird(see 1), but Mail is more turnkey (1-click pairs with MS Exchange)

You can downgrade your O365 licenses to Exchange Plan 1 and keep your email hosting at a tiny fraction of the price of full 365 suite.

(1): Beware thunderbird has an open and unsolved bug that randomly deletes all your emails, kind of like a 1d1 million dice roll.