Import a CSV file to MongoDB with PHP

I am trying to import a csv file into a mongodb collection, I have seen that it can be done through the mongoimport command, however I need to do it through php because I want to validate the entered data afterwards. So far I have managed to open the file and put its contents in columns as shown:

public function storeCSV($upcsv, $coll) {                                

    if(($gestor = fopen($upcsv, "r")) !== FALSE){
        $cont=0;  
        $array = array();
        while (!feof($gestor)){
            $datos = fgetcsv($gestor, 1000, ",");
            if($cont > 0){
                $array = [
                  "Matricula" => $datos[0],
                  "Nombre" => $datos[1],
                  "Edad" => $datos[2]
                ];                                        
                var_dump($array);
            }
            $cont++; 
            $coll->insertOne($array);
        }            
        fclose($gestor);            
        echo "Importacion completada";
    }
    else{
        echo "Archivo no encontrado";
    }
}

The result is the following:

array(3) {
  ["Matricula"]=>
  string(3) "001"
  ["Nombre"]=>
  string(4) "Juan"
  ["Edad"]=>
  string(2) "20"
}
array(3) {
  ["Matricula"]=>
  string(3) "002"
  ["Nombre"]=>
  string(5) "Maria"
  ["Edad"]=>
  string(2) "20"
}
array(3) {
  ["Matricula"]=>
  string(3) "003"
  ["Nombre"]=>
  string(6) "Carlos"
  ["Edad"]=>
  string(2) "21"
}

or its equivalent:

"Matricula","Nombre","Edad"
"001","Juan","20"
"002","Maria","20"
"003","Carlos","21"

Now I want that data to be entered into a collection in mongodb, for this I use the insert () method as it is shown in the code, but when executing it, it tells me that it can not use that method, I have already created a connection to mongo so I do not understand why it does not work. I've also tried with insertOne () and insertMany (), but it's the same.

Greetings and thanks in advance.