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.

That's an issue that would be solved with a better UX on Fairphone's side though, not removing the feature entirely.

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.