How to get custom query param with context.params in getStaticProps with "fallback: true"

[AssisrMatheus]

I have a page that is always generated at runtime with fallback: true:

export const getStaticPaths: GetStaticPaths = async () => {
  return {
    paths: [],
    fallback: true
  };
};

getStaticProps is then ran at runtime for this page. Or else the build process would need to build thousands of static pages, and that's basically the reason to use fallback: true.

I know that getStaticProps can't have custom query params like ?page=2 at build time, because there's no way of knowing that. But how to do it with fallback: true at runtime?

I need to paginate a page, and the data is fetched from the server in the current page, so we fetch only the needed records. Is it possible?