Lit is still supported but we want to encourage new users to use the React option since we expect to focus more on that. You can use GitHub - vaadin/skeleton-starter-hilla-lit as a reference for how to structure a Vaadin 24.4 application with Hilla and Lit.
You can check out Hilla promotes React more than Lit recently? - #6 by Leif for a more elaborate description of how the React and Lit options relate to each other and what to expect in the future.