So I'm just curious about this situation: if I flag my own piece for "inferior post of:[ID of post]" then hit "submit", does my account get any kind of negative thing on it? like a lessened upload count or something?

I wouldn't imagine that, that's the case but I seriously have zero idea how 96% of this website works, lol, so thanks for being patient with me

A deletion (no matter the reason) will subtract from your base limit of 10 unapproved posts, at a rate of 1 post for every 4 deleted posts. Because of your 27 deleted posts your limit is currently down to 4, which is used by the posts you currently have pending.

The upload_limit page explains this in more detail. It would take 40 posts to be deleted with 0 approved before it becomes impossible to upload anything at all. Admins can override this by raising the base upload limit if they believe it's fair to.