Hi @Coco, I’m not sure exactly what you mean by “file and send to the appropriate folder in one movement.”
Alfred is a laucher app that, with the above described addition, allows you to select any menu command that exists by typing rather than mousing. It’s not mail-specific and cannot create a function that doesn’t exist. If the action you want already exists in Mail’s menus, Alfred just lets you select it in a different way.
Apple’s decision to stop Mail plug-ins - in my opinion - is to be a moderate catastrophe. There own mail client won’t be of any use to me because I also use the GPG plugin, which probably won’t work with MailMaven.
If I would switch to any other mail helper solution, all of the data that I entered into MailSuite will probably be lost. Not an option either. 
At the moment I’m still holding out with MacOS 13 - but at some point this will not work any more.
From the MailSuite I mostly use MailTags to define and ensure/organize follow-ups. Apples recently introduced reminder solution is not bad but does not replace the follow-up-capabilities of MailTags.
Does anybody have an idea how I can replace the follow-up capabilities of MailTags under Sonoma and how to export all the follow-up information from MailTags??? 
Thanks, Matthias
Check the possibilities of Mailbutler.