Harvey But Youtube and Twitch would not work before and now do.
You're absolutely right. After a good night's sleep, version 10 worked for me as well. As I recall that whole process, as I rebooted the notification from Solus appeared saying that software updates were available. I was distracted at the time, and thinking that someone had fixed the problem and updated the repository (which has happened before), I went ahead and updated. That, of course, put version 11 back on that machine.
This morning, while not distracted, I went through the process again, and was careful this time not to pay any attention to that notification. And indeed, it works.
The silver lining, as I mentioned, is that Firefox now works for streaming our local TV channels and I was able to remove Google Chrome from our media computer. That was the last instance of it on the whole network. 😄