I am a longtime Firefox user, but time is running out, I fear. About a month ago I was no longer able to log into PG&E, my natural gas and electricity provider. No errors, but the sign-in page would not load on Linux or Windows. Last week, that changed. They print link to a page that says that only Chrome, Edge and Safari would be allowed to login to their web pages. The claimed that no other browser exceeds 5% of users and, rather than spend resources supporting other browsers, they were blocking all of them.
Chase Bank blocks all access from any operating systems except Windows and MacOS. Only those two systems were considered "secure enough" to allow in the door.
I can move to a different bank, but I can't change from Pacific Gouge and Extortion. Oddly, I can use Duck Duck Go on my phone, so I can survive, at least. If a real alternative browser ever is allowed onto Android (not likely without legal intervention), I suspect it will soon be blocked, but as long as all Android browsers are Chrome with a Firefox or other wrapper, it continues to work.
As time passes, the only options will become Chrome based except for Apple products.