In Windows 10, it was very easy to change your default browser:
Start -> Settings -> Apps. Click Default Apps, then click under Web Browser.
But now, under Windows 11, things are rather different. If you want to declare something other than Edge as your default browser, you’ll want to do that through your browser now. In Firefox or Brave, go to the Options (Hamburger) button to the upper-right, then click Settings. In the General panel, look for a button labeled “Make Default”. If you use that, it should do the trick.
Start -> Settings -> Apps. Click Default Apps, then scroll down to click on your browser of choice. A long list of file types will appear; click each of the following, one at a time, and set them to use your preferred browser:
I’m not sure why this is now such a convoluted process, but I’m hoping it’ll simplify after future complaints/updates.