Already in the works :) https://github.com/JojiiOfficial/Matrix-EmailBridge

Doesn't your phone's email app support multiple email accounts? Gmail and Outlook both support mail forwarding too?

The cross-platform client aspect of it (linux in particular) is what I'm interested in.

I used mailspring for a while but it just was too buggy for me unfortunately.

A nice looking cross platform email client doesn't have a lot to do with this concept IMO.

I personally also don't see why you couldn't use different clients on different platforms. They can all link to your email account I the same way.

what do you mean?