Hey there @FoGameru! Welcome to the community! Firstly, this is not legal advice and I am not a legal representative of Epic Games. It is always recommended to verify in the EULA if your specific use-case is excluded. Now that disclaimer is out of the way, yes I believe you are able to use FAB assets with any license besides “Reference Only” and “Quixel Legacy License” in renders for software in other engines, film, etc.
Previously the Marketplace license only allowed for use in Unreal as well, but FAB is meant to be universal so that restriction had changed now that the store also houses assets for Unity and other engines as well with the intention to be a unified storefront instead of a walled garden.
However any Epic released sample and tutorial content must be used in Unreal only as that license hasn’t changed.
The EULA if you’d like to read more:
https://www.fab.com/eula