I just can’t find a decent email client that looks like it’s from the last 20 years. Geary and Evolution both appear to be pretty modern but something about using Gmail with a Yubikey just doesn’t work and neither of them will connect to my account. Both on Fedora and OpenSUSE. Thunderbird works but it’s so old fashioned and Betterbird doesn’t look much better. What’s everyone else using?
Evolution, Thunderbird and KMail, depending on the system. Though I’ve had only trouble with Thunderbird and gpg signing with a yubikey. The others just work.
On Android I’m using FairMail.
On Android K-9 mail is now under the Thunderbird umbrella