I fully appreciate the "not interesting or engaging" part, but I'm confused about the "not realistic" part, considering that widespread racial prejudice is exactly how people behave IRL.
Widespread
racial prejudice is primarily an invention of the Renaissance or later, and it grew out of the extremely unfortunate interaction of multiple societal traditions that were not...that. Remember, Shakespeare had a "Blackamoor" character, and nobody thought that was particularly offensive. Before that, French and English authors in the Arthurian romances included bi-racial and Moorish characters (who had converted to Christianity, of course), and that wasn't considered offensive. Or Miguel de Cervantes, who includes (IIRC) a fleeing Moorish princess as one of the bravest and most noble of the characters in his works. Any controversy about her would have been that he was showing a
woman with such qualities, not that he was showing a
Moor with them.
Prejudices of the medieval period were almost exclusively driven by
religion, far and away more than ethnicity. Further back, again, there doesn't seem to have been any particular dislike for Egyptians by Greeks or Norsemen by Romans, other than to look down on outsiders for their "bar bar bar" language, why couldn't they be
civilized and speak
Greek?
But, much like the idea that the Church burnt witches at the stake, pop history and pop religion often have
literally nothing whatsoever to do with actual history and actual religion. (For the record, the Inquisition burned
heretics--people who failed to practice Christianity "correctly"--at the stake....and it was
literally heresy to claim that witches existed, as in, it was literally, formally in violation of Catholic doctrine to claim that anyone could get power from making a deal with Satan, and accusing someone of that meant
you would get punished, not them!)