Please take a look at the very nice Murena's K9mail fork (https://gitlab.e.foundation/e/os/mail). :
- a very elegant mail list with green dots for unread mails, a preview with 3 distinct lines (sender, subject, preview), a star only if the mail is followed.
- a menu in only one pane much more clever than that of the thunderbird version which allows to select the accounts and to access the settings.
Thanks !
