Welcome to the community forum.
What about a different cable? The cable is important, too. If in doubt, it should help if it is USB-IF certified.
There’s still the odd chance you got a phone with a malfunction, **it happens. You can take that up with your seller or with Fairphone support … https://support.fairphone.com/hc/en-us … or you could return the phone within the given time.
Yes, and for all the right reasons. Why did you get one?
How can competitors be cheaper? Could it be it’s not only mass-production benefits, but also that somebody along the way pays the price the customer doesn’t?
Are you in France? It was reported here in the forum that France forces phone vendors to include earphones when selling their phones. Nothing any phone vendor can do about it in this case.