I have a fairphone 5 and actively don't like it when it asks me if I want to mirror my screen when I plug it into a charging cable attached to a monitor.
Then you can make a tidy profit upgrading to the Fairphone 6 series and selling your phone to someone who wants that functionality. What is the point you're trying to make? We already knew different people have different preferences.
That's an issue that would be solved with a better UX on Fairphone's side though, not removing the feature entirely.