Considering I personally have a very “ethnic-sounding” surname, I certainly do not discriminate against them.
Some of my colleagues would disagree with me on this, but my thought is that there is no earthly reason why an author should have to go by a pseudonym just because some agent or editor is worried that readers won’t be able to pronounce their non-English surname. People who read books are smart. They’re not going to bypass a book simply because the author might be of an ethnicity other than their own. I personally find the idea a little offensive, and I’ve argued with other editors about it before. On top of that, I have met Latin@ children at a city middle school (my friend is their English teacher) who got excited when they read a book by an author with an obviously Spanish last name. If anything, an “ethnic-sounding” last name could be an advantage, to draw in young readers who are tired of reading books by yet another Joe Smith or Robert Miller.
If your last name is Chang, or Dhrtiman, or Ponce de Leon, or Singh, or de Rossini, or Chanthaphonh, or Wiśniewski, or Mohammed, or Ramirez, or Li, or Whistling Elk, or Mbegesi, and someone tells you you have to change it in order to be published… tell that person where they can shove their fucking white privilege.