who is taking over my firefox default browser

I wonder what you have set in Windows 11, maybe a scavenger crow flew in from there :)

This happens every time Microsoft does automatic updates. I use Mozilla Firefox as my default browser but after the Microsoft updates they set the Microsoft Edge or whatever their current browser is for their default. It drives me crazy because they do this to several other preferences I have for settings I prefer over their default settings. You can control how often they will do their updates but I think they only push out for two weeks period of time. Microsoft thinks they own our computers and I own a Dell computer but Windows is a Microsoft product along with the DOS which is the operating system that Bill Gates and Steve Job wrote when they were really young. As you know they went their separate ways and Gates developed Windows and Steve developed Apple. Now we have to pay a royalty fee for all purchased computers because they all run on DOS except for Apple computers. SO go to your settings and read what you want to change and alter it back manually.