SubQuery Not Working

May be it's too late. But you can use "use" in anonymous function if you want to access the variable outside the scope like this :

PHP Code:

$builder->orWhereIn("shop_id",function(BaseBuilder $builder) use ($crsk){
      return $builder->select('shop_id')->from('shops')->where('owner', $crsk);
}); 


No. The problem is that the hint of the BaseBuilder type is not specified correctly.
Expected

use CodeIgniter\Database\BaseBuilder;