How do I get a Stream Key?

I've been streaming on tiktok live, but when I use tiktok live + obs to multi stream, my pc can't handle some games.
I can use tiktok on obs, but I need a stream key. I've been looking into this for so long and I find 0 answerts.

Some answers are "go into your tiktok live and it should be there." It's not
I've read about getting into an agency and they give you a stream key. I have no idea how to find one.

So if anyone can give me an answer I would love it ! Thank you in advance