Interesting, need to check but so far the modern methods of multi protocol messaging was mostly just aggregating the web UIs of the various services in a single application (read: like a web browser)
Pidgin, Miranda, Adium are the things I was referring to - would be cool if I could use them for whatsapp, signal, gmail chat/hangouts but I donβ think thats possible. Happy to get corrected here.
[1] https://www.beeper.com/
[2] https://ferdium.org/