Error Call to undefined function CodeIgniter\Database\MySQLi\mysqli_init() CodeIgniter4

I'm stuck with CI4, I tried checking whether something similar to the input data in database table. but it always shows the above error.

my controller code is

                $source = $this->request->getVar('source');
                print_r($source);
                $destination = $this->request->getVar('destination');
                print_r($destination);

                $model = new BusModel();
                $src_data = $model->getSource($source);
                print_r($src_data);

it works up to printing destination then the CodeIgniter shows errors as shown in the title. Model has the following code

class BusModel extends Model 
{
    protected $table = 'stop_times';

    public function getSource($source)
    {
        if (!empty($source)) {

        $db = \Config\Database::connect();
        // $db = db_connect();
        $builder = $db->table('stop_times');
        $builder->select('stop_sequence, arrival_time');
        // $builder->from('stop_times');
        $query = $builder->getWhere(['stop_id' => $source]);
        print_r($query);
        }

I tried different methods but it always shows the same error