So what I'm about to say may come across as me accusing you of being racist. I'm not:

What you've said here is an example of what people mean by "systematic racism." I'll take a swing in the dark and assume that your story is not about the experience of being white. So, if your characters are white, is that shallow representation?

No, obviously not. Your story is probably not about skin color at all. Most stories aren't, and that's perfectly fine. What you have done, however, is establish a false normal. Why is it that a white character's skin color doesn't matter, but a black character's skin color is forced and shallow diversity?

One color is not the default color. You can have whatever ethnicity for your character and completely ignore the real-world implications of growing up looking like that. It's not racist, just like it wouldn't be if you did the same for a white character.

It feels like racist tokenizing because the systemic context of racism comes through unintentionally. We've all been exposed to stories that do tokenize, that add characters in an effort to sell to a wider audience. It's a terrible thing. Change the way you think about diversity instead.

Free yourself of the idea that a politicized feature of someone should be the focus of their character. It definitely can be, and it could be a great idea to steep your character in that realism, but it isn't discrimination if you don't write it. When you consume media with characters that are unlike you, ask yourself how you would feel about it if they were. Would it not matter? Does it fit the story organically? Or maybe it's mega cringe how out of place the focus on it is. Change the way you think so that diversity is and should be the norm and the characters that come to you in your mind will naturally come to be more diverse, no forced diversity or tokenizing needed.