Your project is doomed to failure unless you actually take the time to understand copyright. You have clearly already skipped that step, so you should go back to it before you do anything else.

For one thing, everything is copyrighted automatically. A creator uploading a work that they just created is uploading a copyrighted work. What you need to do is to ensure, somehow, that only the owner (or a licensee) of that copyright uploads the work.

And no, there is no service or API or ai bot that can help you. If I write a story tonight, I automatically own the copyright on that story and there is no way for that hypothetical ai bot or API to know about it.

Lawyers learn about this stuff in law school. At minimum, you need to find one of their textbooks and read it. Then you need to hire a lawyer of your own to advise you.