qutebrowser author here, use Dodo and can confirm it's basically the qutebrowser of mail clients :)
Development is slow but not unmaintained. The author comes back every month or so to merge PRs. Reminds me I have a bunch of local changes I should upstream...
I stumbled upon Dodo while checking your starred repos, and I think it deserves more attention than it has; it is mature enough to be used by users who wants customizibility, vim-bindings, and easy configuration. It's one of my top options to migrate to as a mail client if I find any problems with neomutt, which I am using right now.
Development is slow but not unmaintained. The author comes back every month or so to merge PRs. Reminds me I have a bunch of local changes I should upstream...