Regarding POC characters *starts to laugh*. I mostly only write as women of color characters. I struggle trying to remember to include and represent white characters.
It used to be quite the opposite for me because, as a teenager, I thought it was customary to write white characters since that's mostly what I read and saw on the screen.
Even though I'm a bi-racial (black/white) person myself!
Side note: I identify most of the time as black--except when people ask if I'm Asian or Latino, I then tell them no, I'm mixed/bi-racial (black/white).
So then I went to a convention session one summer in High School that spoke about the lack of representation of POC in film, books, TV, and comics and was like... well, Holy Shit.
I'm black, and I'm adding to this problem!
I now strive to find fiction/fantasy books about black female protagonists and other WOC (women of color) as the protagonist.
And since I want to read/watch more about them, I mostly write WOC characters to help get more "coverage" out there. LOL.
Now my goal is to get educated more and consume more entertainment about LGBTQ+ characters.
On the topic LGBTQ+ characters, I've only enjoyed writing as asexual or gay characters (I mean other than straight). Bi-sexual and pan-sexual characters are hard for me to write well. But I understand it shouldn't be since, like others have said above this post--WE are ALL human in the end. And I know there are even more different orientations, but I still need to learn more about them before writing tales from their POV. Like I said I'm open to being educated more. Regarding trans characters, I've only written as one FTM trans character in the past, but even then, I barely ever mentioned their 'trans' identity as it wasn't imperative to the story... but then I felt like I was doing the whole 'hiding/closeting' thing. So, unfortunately, I started to avoid that situation instead of learning more.