I'm gonna be honest with you, I don't have a secret technique, it's mostly vibes. I guess my main piece of advice would be... don't let your fear of "making rape victims look bad" hold you back. But that's a bit vague, so I'll elaborate.

Since you like Lynn so much, let me use her as an example: she's a survivor in more ways than one, has gone through terrible things, comes from a low class background, she's a woman of color, and she's also completely morally depraved and generally a pretty shitty person. But somehow, when you read my work, I don't think your takeaway is "she makes lower class people/Asian women/rape survivors look bad". Instead, what you think is "this is an interesting character"!

If you focus on trying to write a character that will "represent" a large number of people, you will end up representing no one, because every person is unique, and there's nothing particularly interesting about some vague depiction of any group of people. Instead, you should be as specific as possible. What makes this character of yours stand out? Why are they the way that they are? What makes them tic? What are their flaws, what are their qualities? What are their weird quirks, or instead how do they conform to societal expectations? Those are the things people are going to remember, and also why they're going to bond with your character, be it because they relate to that character, because they don't relate to them at all, because it makes them think of someone they know, or because that character is unlike anyone they've ever met.

It's of course entirely possible that you'll end up accidentally writing something offensive. Don't be afraid of it! Sometimes being offensive is bad, but sometimes it's good. Think about how that offensiveness impacts the work and the people that read it. If you see it as a net negative, then by all means, do some research to try and fix it. But if there's something good you can get out of it, keep it. Share your work with people who won't jump at your throat at the slightest mistake, hear out constructive criticism (you're free to take it or leave it), and ignore blind hatred.

If your nerve allows it, I should remind you my DMs are open! If you wanna show me what you're writing and get direct feedback from me, I'd be delighted to give it, as your idea seems like it has a lot of potential!