How might the world change if every person made it their mission to understand and embrace racial differences?

Society hasn't been more openly racist in a long time. The movie "The Society of Magical Negroes" demonstrates this explicitly. There's a lot of efforts to seed division between races of people, especially from people who claim to care about "equity."

I think the we'd have an easier time accepting everyone and every culture even if it's something that we don't fully understand or agree with.

More people would have a deeper understanding of others and become less judgemental and reluctant to accept change. This would improve the world's fairness and socialness.