i'm trying to post js array of keys and values to php using axios and am really lost thanks for your help

here is the array i'm sending:

 let arr = [];
    arr["adID"] = uuidv4();
    arr["price"] = price;
    arr["city"] = city;
    arr["street"] = street;
    arr["rooms"] = rooms;
    arr["building_number"] = building_number;
    arr["entry"] = entry;
    arr["apartment"] = apartment;
    arr["user_id"] = 1;
    sendDataFromJsToPhp("insertAd", arr);

here is the axios part:

 sendDataFromJsToPhp(type, parametersArray) {
this.formData.append("data", "insertAd"); //type to create new ad is insertAd
this.formData.append(
  "parameters",parametersArray); //type to create new ad is insertAd
axios({
  method: "post",
  url: this.url,
  data: this.formData,
  config: { headers: { "Content-Type": "multipart/form-data" } },
}).then(
  (response) => {
    console.log(response.data);
    this.resultFromServer = response.data;
  },
  (error) => {
    console.log(error);
  }
);
//this is a work around that will get us array of keys and one of values and will merge them
//to get aray that represent the data we got
return this.resultFromServer;

}

here is the php:

header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Headers: *");
header("Access-Control-Allow-Methods: *");
header('Content-Type: application/json');


$DATA_RAW = file_get_contents("php://input");


$DATA_OBJ = json_decode($DATA_RAW);
$error = "";
 if(isset($_POST)&&isset($_POST['data']))
$dataType = $_POST["data"];
if(isset($_POST)&&isset($_POST['parameters']))
$parameters=$_POST['parameters'];
print_r($parameters);

the errors present when i address the $parameters i get these errors: 1)Warning: Uninitialized string offset 0 in 2)b>Fatal error: Uncaught TypeError: Cannot access offset of type string on string in

thank you very much