How can I convert the following raw SQL into CodeIgniter's query builder methods?

$this->db->query('
    DELETE FROM default_model
    WHERE cat_id NOT IN (
        SELECT id
        FROM default_category
    )
');

I tried with:

$query = $this->db
    ->select('id')
    ->get('category')
    ->result();
                  
$this->db
    ->where_not_in('cat_id', $query)
    ->delete('model');

I tried a lot of things, but could not do it. How can I resolve this?