You don't tug on Superman's capePerhaps a little unfairly I abandoned Apple Mail over 6 years ago. Got sick of fixing issues with my wife's gmail accounts in Mail. To be fair to Apple obviously that was a while ago and a lot has changed since then but at that time I swapped to Airmail and never had any problems for myself but I became disillusioned with Bloop (the developer) after a few years when they suddenly moved to a subscription based model so I swapped to Spark Classic. Absolutely brilliant email app in my opinion.
This is still free and works on all my devices, now if only I could convince my wife to swap too.
You don't spit into the wind
You don't pull the mask off that old Lone Ranger
And you don't mess around [with the wife's email]
- Jim Croce if he knew about email