The Unified Will Versus the Individual

Schopenhauer rejected Kant because causality is just a form of the understanding, right? But his alternative is unity, right? And the dual aspect theory, it's one same thing. It seems to me any system like this will fall prey to the same sorts of objections. Once you've said that everything by which we understand things is, I guess it comes back to the intuition, the non- representational experience thing, but it's problematic.