Hi @fooddolly,
By default WordPress, Rest API returns 10 users that are mentioned in the official documentation.
See the reference: https://developer.www.ads-software.com/rest-api/reference/users/
You can get all users even they have not created any post, for that you need to modify the response with the simple filter.
// Use this filter to modify the default response in your functions.php
add_filter( ‘rest_user_query’ , ‘fooddolly_rest_user_query’ );
function fooddolly_rest_user_query( $prepared_args, $request = null ) {
unset($prepared_args[‘has_published_posts’]);
return $prepared_args;
}
Hopefully, it will fix your issue.