Also from
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe
sandbox
Applies extra restrictions to the content in the frame. The value of the attribute can either be empty to apply all restrictions, or space-separated tokens to lift particular restrictions:
But if you add more than Twitch needs, Twitch doesn’t honor/add the extra permissions, hence trying to override the X-Frame-Options does nada.