Fourth

Fourth: Firefox must be fixed to work correctly again.

It simply doesn't work correctly with many modern web sites anymore.
That's a recent phenomenon.
In the recent year or two I was forced to open Chromium more and more often because the website simply didn't work in Firefox.

I didn't even have a second web brower installed for about two decades, until two years ago.

People are running away from Firefox - for a reason.
The only reason I still use Firefox is that there is no alternative with equivalent Firefox compatible plugin support and trustworthiness.