capetlevrai Flarum only uses some components of Laravel, not Laravel as a whole. There are also components from Luminas (Formerly Zend) and other places as well. Laravel truly is for the most part it's completely separate framework built upon to pieces and parts of other frameworks.
Also you already can use Flarum 🙂 even though it's in "beta" the user experience is extremely stable and the beta tag is more representative of the current extension developer ecosystem.