WP REST API Controller Create Items

<?php
class Sports_Bench_Team_REST_Controller extends WP_REST_Controller {
  /**
	 * Create one item from the collection
	 *
	 * @param WP_REST_Request $request Full data about the request.
	 * @return WP_Error|WP_REST_Response
	 */
	public function create_item( $request ) {

		$item = $this->prepare_item_for_database( $request );

		if ( function_exists( 'sports_bench_rest_add_team')  ) {
			$data = sports_bench_rest_add_team( $item );
			if ( is_array( $data ) ) {
				return new WP_REST_Response( $data, 201 );
			} else {
				echo 'not created';
				return $data;
			}
		}

		return new WP_Error( 'cant-create', __( 'message', 'text-domain'), array( 'status' => 500 ) );
    
	}
}

function sports_bench_rest_add_team( $item ) {

	global $wpdb;
	$table_name = $wpdb->prefix . 'sb_teams';
	$team_name = $item[ 'team_name' ];
	$slug_test = $wpdb->get_results( "SELECT * FROM $table_name WHERE team_name LIKE $team_name" );

	if ( $slug_test == [] ) {
		$result = $wpdb->insert( $table_name, $item );
		echo $wpdb->last_error;
		if ( $result ) {
			return $item;
		} else {
			return new WP_Error( 'error_team_insert', __( 'There was an error creating the team. Please check your data and try again.', 'sports-bench' ), array( 'status' => 500 ) );
		}
	} else {
		return new WP_Error( 'error_team_insert', __( 'This team has already been created in the database. Maybe try updating the team.', 'sports-bench' ), array( 'status' => 500 ) );
	}

}
?>