In my opinion, the #1 way to make Gmail better is to enable forwarding. Then you don't have to deal with their ugly interface, login system, new features, weird compose window, etc....
Outlook is unusable but harmlessly so. What's worse is Microsoft 365. I simply can't find a way to configure 2FA in any kind of sensible way. Right now it's simply turned off, which makes me very nervous. Whatever I do, it is somehow overridden in other parts of their byzantine and always changing cat herd of admin sites. I'm waiting impatiently for our M365 subscription to expire so we can finally migrate off this nightmare.
i tried to migrate from Workspace to iCloud but dealing with the insane OSX Calendar app which not only does not put anything into your itinerary automatically but is liable to just disappear items from the Calendar randomly, put me off so much i went right back to Workspace.
I even dug out my computer that was logged in to this account in desktop browser, and it too blocks access. Crazy.