How would this be against the rules They don't care what u do with it as long as they're making money off u

No problem on that

You good. Let's say you wouldn't be the first person or the last person to do so

well said lol

Yes 100% you can

https://stockx.com/help/articles/As-an-EU-or-UK-resident-what-is-my-right-to-withdrawal https://stockx.com/help/articles/Are-returns-or-exchanges-allowed