There’s a link to the rules page on the page.
https://epicgames.box.com/s/jvivupkx…ux5ntzidpvqjw8
This seems like it’d be the relevant section in regards to your question (I can’t speak for Epic, just helping you look up the answer).
“As a condition of entry, Contestants hereby provide a non-exclusive, irrevocable, perpetual, worldwide license to Sponsor to use the Submission in any and all media throughout the world for the purpose of promoting the Contest and future versions of the Contest and Sponsor’s Unreal Engine marketing, but for no other purpose, without any additional compensation, the term of which shall be the entire life of the copyright.”
Sorry, I’ve already got my own Quixel account, so I can’t test it.