How to specify excel rows quantity for import

Question

I'm using maatwebsite/excel 3.1,when importing excel file with 5 rows and 34 columns of data, it takes 500 rows and each row contains 703 columns and I need to decrease memory usage.

How to specify rows quantity and columns too?

...
 public function collection(Collection $rows)
    {
      ...
      foreach($rows as $row){
        if (!$row[0]) {
            return;
        }
        ...
        $productArray = [...]
        $this->product = $this->importProduct($row, $productArray);
       }
    }
    ...
   
    public function chunkSize(): int
    {
        return 350;
    }