What I _wanted_ to do was to use Apple Mail on my Macs. I even did it for a while. Mail’s simplicity is comforting and it makes mail look nice.
What I ended up doing instead is to go back to MailMate.
I have 3 mail accounts; Gmail, Fastmail, and Protonmail. I would like to manage Gmail and Fastmail from the same app. I tried using their respective web apps but I just don’t enjoy it. Never have.
Apple Mail sometimes goes wonky on me and I never seem to figure out what causes it. This time, for example, all of my messages sent from Gmail ended up in my Fastmail account’s Sent folder. I tried every combination of changing/removing/re-adding SMTP credentials/servers/accounts but could not get it working right. I then started seeing messages in “smart” mailboxes that should not have been there. Considering how much time I spend in email, these little annoyances add up.
MailMate is a little “heavier” and not as pretty, but it has always worked flawlessly for me and does everything I could ever want.