I actually just experienced it a week or so ago, it just appeared on my taskbar, chrome disappeared and my default browser suddenly became edge. Was pretty pissed, figured it was just something I did, but then I thought, that's a LOT OF steps I would need to do, so I just figured it was a part of an update. I swear, one day I am going to switch fully to OSX.
Happened to me as well. Still using FF in spite of it.
I'm only using this W10 laptop cause my Ubuntu tower is in need of repair. The power button is messed up.Finding a computer repair-person during a pandemic is quite the undertaking.