I spend most of my day in the command-line, so aerc[1] is my preferred email client — the only one, really. Since I like signing my emails with PGP as well, I compile it with this patch[2] and enable signing by default. Before that I was using mutt[3], but the layout chosen for aerc is simply miles ahead in my opinion.
On mobile, I use FairEmail[4], but only to receive server and emergency notifications. If I am off the clock, a server on fire is the only thing that should get me back in front of a computer.
[1] https://aerc-mail.org/
[2] https://lists.sr.ht/~sircmpwn/aerc/patches/14523
[3] http://www.mutt.org/
[4] https://email.faircode.eu/
