I have this code to get API data from

As a confirmation, we can see that the module is indeed not supported (and will not be) by Nuxt3 on the modules page.

The Suspense error is detailed in the official documentation

<Suspense> is an experimental feature. It is not guaranteed to reach stable status and the API may change before it does.

It may seem scary but you can totally use the API as per se and since it's a warning and not an error, it's totally fine!