lower control arm 1972 Duster

You seem to be moving the goal posts to suit your postulation. Stating everything flexes in an engineering sense is only stating the obvious. The LCA's are not flexing in ANY significance, they maybe moving longitudinally slightly on their pivot points. If this nearly 3.5" nearly boxed 11g(?) pseudo I beam LCA is overly flexing in your view, you then must be horrified by the QA1 1.5"(?) tube LCA set-up. In this attached video. you do see movement that the strut is intended/designed to control, and that is mainly under braking. I don't see the significant importance here of this video. What am I missing? The LCA pivot points were never intended to be rigid in more then two axis. The fact remains the strut and the LCA have conflicting arcs which you claim is not a factor because of its insignificance but the slop is significant, without basis, on this thread the slop has been antidotally by another to have only been noted/observed only when backing up. Your contention(?) of the longitudinal LCA slop and LCA flex, real or imagined leading to vague steering responses is still without basis.

Edit: I did see the lack of something maybe in the video. If as claimed the LCA was flexing and or rotating, the strut rod that is rigidity attached to it, and is approx. 16" long, would visually significantly amplify any rotational flexing of the long axis of LCA, as would be seen on the rubber mounted bolted end of the strut rod. I saw no detectable movement vertically nor bending of the strut rod nor unexplained distortion of the rubber bushing. Most movement seen was reaction to the braking action firstly and then normal compression/rebound action. Adding a temporary telltale brake light indicator in the video would help in future recording to distinguish suspension inputs.