Hi Opcode,
I can't give you a definite answer either way but here's a few things that I can tell you. I always check Freshports and Linux from Scratch for applications to see how difficult they are to build. Freshports nailed the official signal client:
https://www.freshports.org/net-im/signal-desktop/
It has Electron. With enough time and money electron could be ported but it's not really worth it, it'll run like ass.
Next I found this:
https://www.freshports.org/net-im/libsignal-client
It uses Rust, which isn't viable for IRIX. So thes went in the bin.
Bottom line I've not found a client that works but it might be possible to bounty a client to be made.
XMPP clients and IRC are the main chat apps that work for IRIX. SGUG has libpurple, which is part of the pidgin application. From screenshots it seems to work okay but I don't use the RSE. It's not my thing.
I have a couple of xmpp clients that I have successfully built and a couple that I need to research at some point but I haven't had the time to release much of my findings. I finally finished renovating my office recently but I then got roped into helping my neighbor peel off wallpaper for the last 3 weeks, Plus work slamming me plus a whole bunch of other things.
My suggestion would be to continue to do some research and figure out what you actually want. It's possible that through a joint bounty that we could raise a couple thousand dollars and somebody might be willing to develop a Motif chat application for something like signal, but of course that's a lot of money that would need to be raised. My main personal things right now are replacing the toolchest and creating another text editor. So that's taking a lot of my time.
I'm the system admin of this site. Private security technician, licensed locksmith, hack of a c developer and vintage computer enthusiast.
https://contrib.irixnet.org/raion/ -- contributions and pieces that I'm working on currently.
https://codeberg.org/SolusRaion -- Code repos I control
Technical problems should be sent my way.