Hi,
Thank you for the details, it helps a lot!
I see a few issues in your configuration. One, is that the redirection is set to a custom URL, but it seems to be copied incorrectly. The custom URL, you want is exactly the same as choosing to redirect to the WooCommerce results page, so I recommend using that instead.
Secondly, I’m not sure, if you don’t want products as results, but currently, the products custom post type is not selected.
The issue with the product attributes as search results is actually not an issue, that is unfortunately the correct product attribute link, that WordPress returns via get_term_link(..) calls. The one you want, is some sort of a pre-defined filter trigger to the shop page. It could be possible to construct that via custom code, but I am not sure how to request that URI scheme, or where it comes from.