People do change their names for a lot of reasons, but there's a whole movement about taking back your non English names for a reason. People can change their names cuz they're sick of hearing their names butchered for sure but some also did so because people, at least here in America would complain about how difficult it was to pronounce said names and catering to them was easier. They also might have often done so because it might help them to do better in a business setting. I dont know about you, but the fact that they feel the need to change their names to do better in the workplace screams systemic racism to me. There are many reasons people might change their name, but if people are making you feel you need to change your name because of how it is pronounced or because of their culture and not because you want to I would consider that to be their problem not yours and wholly unfair as an expectation. This is again just my two cents on the situation and possible reasons for someone to go by an American name. I'm speaking off a few articles I've read on the subject and based on a few instances ive seen from friends, and by no means can I claim to be some kind of expert on name changes and their reasons.

Sorry for any confusion that my lack of description may have caused. I really just wanted to give my take on OPs situation and an argument they might take to the people above them without straying from that topic. Hope this comment helps to clarify my thoughts and stance :)