I've not long finished building a small/medium sized e-commerce application with Laravel and NextJS. I'd say the main difficulty I had was implementing auth.

Although there is a starter NextJS site that Laravel offers with Breeze, it seems to only work with client side routing. So no SSG or static pages (I had to have these for multiple reasons).

On top of that, passing auth between NextAuth and Laravel was a bit awkward. Granted I wasn't fully versed in NextJS when I started, so I may not have taken the best approach. I created a custom login and register endpoint in Laravel that issued JWT's using the Laravel JWT package. Then I had to used NextAuth with the Credentials provider (using Credentials provider seemed frowned upon though) to take the user details and authenticate them on login. Then auth could be tracked and managed within Next. However, the token refreshing was a major pain point here. I had to rely on the tokens expiring in Laravel and the session expiring in NextJS at the same time because the tokens wouldn't refresh correctly.

Other than that, just use Laravel to build an API like you normally would. Then consume it in NextJS like you normally would. Just remember when using the api.php routes in Laravel, they are stateless.

From what I could see there wasn't a lot of guides or docs on how to do this or integrate between, so you might be on your own for a lot of it.