How to make certain posts not appear on the main page, but instead only a newly created category(in the menu section)

You can exclude posts in the “Reviews” category from the main feed using the pre_get_posts hook and some WP_Query knowledge:

add_action( 'pre_get_posts', function ( $wp_query ) {
    if ( ! is_admin() && $wp_query->is_main_query() && $wp_query->is_home() ) {
        $wp_query->set( 'category__not_in', 4 );
    }
});

Here I’ve assumed the ID of the category is 4, you’ll need to find out what yours is.