Can a writer create a character without including the writer’s biases?

Ask the question a different way: Can a person describe someone they know without including their own biases?

In theory it’s possible but in both life and in writing, it’s hard because we don’t really know anyone except ourselves and others like us.

Which is why black people are best at describing the black experience, women are best at describing female experiences, Native Americans are best at describing Native American experiences and so on.

Problem is, there isn’t always someone around with the expertise required to do an accurate job of describing anyone. So we do the best we can.

By the time we’re done, if we’ve been honest enough and worked hard enough to see from that other person’s viewpoint,  then the completed description will probably be okay if not perfect

Perfection is rare.

In writing, if a writer works hard enough, that character will become real to the reader. In life, they may become a friend.