If you want to move the category description below the sidebar on mobile you can try this PHP snippet modification of the one I’ve previously provided.
add_action( 'wp', function() {
remove_action( 'generate_after_archive_title', 'generate_do_archive_description' );
if ( is_archive() ) {
add_action( 'generate_before_footer', 'generate_do_archive_description' );
}
} );