The Diversity Question: The Struggles of a White Female Writer on Writing a Variety of Characters Without Cultural Appropriation or Stereotypes

     As I approach my next novel, I am struck by this plaguing thought. How do I - a nearly translucent white woman of mainly Celtic and Western European background approach diversity in my writing. If I make my next protagonist a person of a different color and ethnic background than I am - is that cultural appropriation? Do I have any right to write from the perspective of something I don't know personally? Or do I add supporting characters of different ethnicities and backgrounds?

     See the first feels wrong to me. I do not know what it is like to grow up Mexican or African American or Vietnamese or Iraqi. And there are so many amazing writers of those backgrounds now finding their literary voices. I have no right to tell their stories. But then that leaves me adding my diverse characters as supporting players, like I am shoving them to lesser roles. The stereotype of the ethnic sidekick.
     Or I fear it will ring false. Like I am adding the lesbian character or the Mexican love interest so I can seem modern and inclusive. I want it to be organic. In my last story, the love interest was Mexican American purely because I was modeling him after my husband who is hispanic. But I didn't give him any ethnic characteristics other than his last name and skin tone because that's how assimilated my husband is. So I am writing from what I know. And admittedly, sometimes that is limited. I do have diverse friends but most of them are either heavily assimilated.
     But I worry that being a straight, middle-class, white woman my diverse characters will automatically be seen as my knee-jerk politically correct inclusion. Like a writer's version of affirmative action. I read one book recently where the main character was an overweight Mexican American girl with one transgender friend and one African-American friend and it felt like the author was ticking off boxes.
     Then I was considering writing a story about a Welsh 13th century prince which would stretch me into writing another gender but not much else. Though I have heard people say that is lazy writing and that there must be a Muslim or Jewish or African character that was historically around at the time and more research will dig them up. And I want to honor the truth of history and be multi-everything and open-minded in my writing. I get that people want to see themselves represented in literature and the arts. I was excited that Belle had brown hair and eyes like myself after blonde blue-eyed Disney princesses shoved down my throat. And that no way even compares to the lack of representation in movies and cartoons of other races. But I don't want it to be feel forced or staged.
    I really want to open up an intelligent dialogue and discuss how to represent a diverse, global world in my writing but in the most organic way possible. I want to be sensitive to other people while telling my own stories. And yes, my main characters will still most likely be nerdy, white girls like me, I'd like to be inclusive of others.
     Just wondering the best way to go about it.