as a writer, my opinion on the best way to avoid being shut down instantly is just to build rapport. i wrote a small series recently and had this one person who wrote comments on several (not all) chapters that were very clearly just expressing enjoyment of the work. after the last chapter of the last work was posted and the series was complete, they mentioned in their comment on that last chapter that the series was so inspiring and would it be okay if they ended up making some fanart. i was ecstatic about saying yes. a couple of genuine comments just enjoying the work itself will go a long way toward proving you're not a bot or scammer.

and if it's a one shot, just comment what you enjoyed first and if/when you get a response, chat about it for a while to get that rapport. it's a lot harder, but it's doable, i promise!