Ok so first I decided I better uninstall the apt version of qutebrowser and try the Flatpak in the Software catalogue. I did that but it also had the same unsupported browser message on any forum I went to that uses Discourse.
So my next most logical approach would be to use qutebrowser for everything except sites that use Discourse. Keep Firefox installed and use it for sites that use Discourse.
So that is still a viable option but in this instance I decided to take the irrational approach of what the qutebrowser docs call:
Installing qutebrowser with virtualenv
Don't ask me what that means, but I followed the documentation, and then the 2 error messages I got, the best I could and the result is a qutebrowser that is supported on Discourse forums:
as is clearly shown in the image above, as now I can sign in and before it would not let me sign in or view any rich content.
Edit: to add to @zenzen I wanted to try your solution and I feel it would have been the simplest solution if I had been able to figure out what I was supposed to be changing. But I think I was super tired after work and it just wasn't clicking for me.
Also editing that I was mistaken when I thought the qutebrowser I had originally installed was the latest version, it was just *the latest version I had seen when searching the apt for other versions and I wrongly assumed that meant it was the most recent.
Edit:
For completeness I am adding that I followed this excellent tutorial by @HanneMaes to make a launcher for qutebrowser venv so that I could pin it to the taskbar where Firefox used to be and have it show up in the Internet section of the Zorin menu. I also set it as the default browser.
