Best developer friendly email client for macOS?

Help the developer community and suggest an email client for MacOS that truly is the best according to you.

It feels like no developers I know is particularly happy with their (GUI) email client on MacOS.

I'm looking for one that:

  - Stays out of my way and lets me focus on emails.
  - Easy to use without a mouse
  - Minimal amount of clutter
  - Unifies Gmail / Google inboxes and sent emails
  - Doesn't cache every single email on my hard drive
  - Probably more, but you get where I'm going

Clients I've tried extensively:

  - Spark - By far the best I've tried so far. But, and it hurts... I choose not to use them now that Ukraine is being invaded both geographically and digitally. In this case I'm rather safe than sorry.
  - Apple Mail - it works, but sparks absolute zero joy.
  - Twobird - I wish I loved them and I do in 80% of the cases. But they want to merge your todo list and email and as a consequence they don't allow you to archive an email without clicking - two times. There are other similar examples caused by the fact that they really want to be a mix between a todo list and an email client.
  - Airmail - "Apple Design Award 2017 Winner". 2017.
  - Mailbox - Discontinued after Dropbox acquired them.