Bedrockgames
I post in the voice of Christopher Walken
I hope you can appreciate that there are reasons why we talk now of Mumbai and not "Bombay" or Sri Lanka and not "Ceylon." Likewise recent events saw many people learning to how to say and spell "Kyiv" rather than "Kiev" or "Ukraine" rather than "The Ukraine." Plus there is Derry or Londonderry. How you choose to call these places is both a cultural and political matter that can communicate how you view them.
I think this is complicated and very situation dependent (and potentially getting us into political stuff). I will say there are definitely instances where I prefer the local name of a place for political reasons. But most of these cases are actual differences in name rather than just regional differences in pronunciation. The difference between Derry and Londonderry isn't the same as the difference between differing pronunciations of Appalachia. Londonderry is an actual name change from Derry and part of a conflict that we can't really get into here.