A little over a month ago, after * long * time switching between email clients like Spark and Airmail, I decided to abandon everything and go back to using Gmail natively enjoying, by the way, the debut of a new version of it with a renewed interface, a feature to postpone (snooze) emails and more.
Although both of the aforementioned customers and a few others that I tested are very good, they are far from perfect and I ended up realizing, over time, that they were more disturbing than helping. I mentioned this in a post on my Facebook:
As for point 1 that I mentioned, some people quickly gave me the tip of Kiwi for Gmail and have been using it ever since.
The Kiwi is not really an email client. It is a part application that accesses the Gmail interface itself in the browser, but it is not a simple window with a web view.
The application supports multiple Google accounts with tabs, colorful themes, the ability to write messages in a new window, universal shortcuts, notifications (email messages classified as important, if you want), icon for the menu bar and more. For those who use the Boomerang service, Kiwi is also compatible with it.
despite ?For Gmail? in the name, Kiwi is not just for accessing Google's email service. It is also integrated into the entire G Suite, allowing you to open documents in Docs, spreadsheets in Sheets and Slides presentations, manage your appointments in Calendar, attach files from Drive, among others, including an intuitive toolbar for quick access to these web apps.
And the best part: for a limited time, you can download Kiwi for free from the Mac App Store (it usually costs R $ 33 / US $ 10)! If Google ever launched a Gmail app for macOS, it wouldn't be much different than Kiwi.