I used to use firefox till I was getting switched to bing which I detest.
Also, I cannot remove the switch to bing in firefox so I made duckduckgo my home page.
I use firefox exclusively on my three systems XP Pro, win7 and win10 and I have set my default browser to firefox in all three operating systems and no
If however this is about switching the browser to Bing (rather than search engine) as far as I’m aware avast has no functionality in that regard, switching browser).
I wasn’t even aware there is a Bing browser (until seeing your post), Edge in win10 yes. But Bing appears to be a browser that you can download for win10.
You can set the default browser in your OS Settings.