How to change Bing Search to my default search engine in Firefox?

After installing Microsoft's Outlook app I noticed that when going to search for something on the Internet by selecting text and searching, I am forced to use Bing instead of my default search engine (Google). (Screenshot from Firefox) I have just found out that this is a known issue mentioned by Android Police in 2020 . I use Firefox 90.1.3 (Build #2015824995) on a Samsung Galaxy S10 and Google is always set as my default. I even removed Bing from the options, yet it is still there when trying the selection search. I noticed that when using Samsung's Internet Browser, there is the extra option of 'Web search' as well as 'Bing Search' and using 'Web search' goes to my default search engine. That is not on Firefox. Is there a known way to stop this intrusion into my right to choose which search engine I use when using Firefox? @Robert indirectly made a good point on settings within Outlook within comments so I had a look. I am forced not to use my default browser as I cannot set it in Outlook (see below) Tapping on the slider does nothing