What I want is a unified (?) comms client. Email, SMS, RSS, notifications, etc. in a single dashboard.

They all have the very similar properties. Sender / source, subject, body, attachments, etc.

And I want to make it easy to tag / organize them. Maybe a tab for each type + tags within each. Search across all (since too often I forget the medium of a particular msg)

Finally, I don't want the provider of this service / client reading the content and generally probing the sphincter of my privacy.

Thunderbird once had a chat extension that worked great. It supported the big protocols - including Yahoo, AOL, XXMP, MS Messenger, and IRC I believe and a whole slew of lesser known protocols. I had to stop using it when the world embraced Skype and everyone moved there, probably around 2006 or so I think.

Today, most chat protocols have the same flaw as Skype: hostility towards third party clients.

I've been using matterbridge[1] to bring all sorts of 'modern' non-standard-compliant chat services back to my irc client[2]

[1] https://github.com/42wim/matterbridge

[2] https://xkcd.com/1782/