Thank you very much for the warm words. Mail clients are surprisingly tricky problem and it took way more effort than I initially anticipated :)

For example, I'm using catch-all address with fastmail. I wasn't able to find any client with the right design that would allow me to define sender address and email account separately during composing, so I can use "alias@test.com via me@example.com" as a sender.

You can send "ping me when linux available" and I'll follow up.