PHP - Insert Key=value Pair In Array After Given Key

I'm trying to insert array of posts categories into MySQL. I'm getting category IDs from drop down list..

ERR: Notice: Notice: Array to string conversion in C:\laragon\*********\includes\functions.php on line 477

Array

Array
(
    [0] => Array
        (
            [0] => 4
            [1] => 5
        )

)

PHP

try {
        $sql = "INSERT INTO posts_category_ids (post_id, category_id) VALUES";

        $insertQuery = array();
        $insertData = array();
        foreach ($filter_category as $row) {
            $insertQuery[] = '(?, ?)';
            $insertData[] = $id;
            $insertData[] = $row;
        }

        if (!empty($insertQuery)) {
            $stmt = $this->conn->prepare($sql);
            $stmt->execute($insertData); //477
        }


         }catch (Exception $e){

            echo $e->getMessage();
}
}

Hi,

I am creating a new menu (food) in my system.  This consists of a menu, menu_items and menu_connection table.

I can insert the menu name just fine and return its id just fine.

When inserting the menu items, i need to get each of the menu_item_ids to use in the query that inputs the menu_connection.

This is what i have so far:

if ($_SERVER['REQUEST_METHOD']=="POST") {
	/////////////////////
	//menu name insert //
	/////////////////////
	
	$mname = mysqli_real_escape_string($conn, $_POST['newMenuName']);
	$stmt=$conn->prepare('
	                     INSERT IGNORE INTO ssm_menu (menu_name) VALUES (?);
	                     ');
	$stmt->bind_param('s',$mname);
	$stmt->execute();
	$menuInsId = $stmt->insert_id;
	echo $menuInsId;
	$stmt->close();

	/////////////////////
	//menu item insert //
	/////////////////////
	
	$mitname = $_POST['newMenuItem'];
	$stmt=$conn->prepare('
	                     INSERT IGNORE INTO ssm_menu_items (menu_item_name) VALUES (?);
	                     ');
	foreach ($_POST['newMenuItem'] as $k => $nmItem) {
		$mitname = mysqli_real_escape_string($conn, $nmItem);
		$stmt->bind_param('s',$mitname);
		$stmt->execute();
		$menuItmInsId = $stmt->insert_id;
		echo $menuItmInsId;
	}
	$stmt->close();

	///////////////////////////
	//menu connection insert //
	///////////////////////////

	
	$stmt=$conn->prepare('
	                     INSERT IGNORE INTO ssm_menu_connection (menu_id, menu_item_id) VALUES (?,?)
	                     ');
	foreach ($_POST['newMenuItem'] as $k => $nmItem) {
		$stmt->bind_param('ii',$menuInsId, $menuItmInsId);
		$stmt->execute();
		$connectionInserId = $stmt->insert_id;
		echo $connectionInserId;
	}
	$stmt->close();
}

Currently it is inserting each of the items in the connection table with the same id - i understand why but i dont know how to collect up all of the ids to use later

UPDATE staff SET staff_last_login="NOW()" WHERE staff_id="1" 

array('staff_last_login'=>'NOW()')

$i=0;
for($i){
$homerider=$home_rider[$i];
$homeorder=$order[$i];
$homesql="INSERT INTO tbl_lg_rider_order (`name`,`card_id`,`homeaway`,`riderorder`) VALUES ('$homerider',$card_id,'h','$homeorder')";
echo $homesql;
$i++;
}
$i=0;
for($i){
$awayrider=$away_rider[$i];
$awayorder=$awayorder[$i];
$homesql="INSERT INTO tbl_lg_rider_order (`name`,`card_id`,`homeaway`,`riderorder`) VALUES ('$awayrider',$card_id,'a','$awayorder')";
echo $awaysql;
$i++;
}