Thunderbird will support matrix protocol out-of-the-box in version 102 (due June) and is available in v91 beta now.
I just tried it, you go to preferences, edit config, add a string “chat.prpls.prpl-matrix.disable” and set it to false and matrix becomes an available option in the chats part of your account setup…now to find my old password…
Was completely unaware of this, it’s pretty cool!
I just tried it and it’s still a bit wack, but it’s also still just a beta.