Seamonkey or claws mifht be good alternatives too.
replyHow is KMail and Evolution at this point? I have not tried them in like 10 years. Are they actively maintained and a real alternative for serious email use?
replyBoth are ok last time I tried (last year?) but Geary is default on Gnome distro's now I think [0]. Geary is much more minimal though.
replyI myself am pretty spoiled by Protonmail I think, really enjoying that.