I was about to post exactly the opposite advice, but your post changed my mind, at least conditionally. The key concept is "appropriate". Extra variable names only reduce the "cognitive load" if both variables have appropriate names and scopes. I once had a customer who insisted that we always use the extra names. Any advantage was lost because he also insisted that all variables be named 'parmxxx' where xxx was a serial number he assigned.

I often use your technique of breaking up complex statements on "Schwartzian Transforms" (Refer to How do I sort an array by (anything)?). I almost never code them right the first time. I usually rewrite them in the idiomatic form after I am satisfied that they are correct.