Fe/GAA on a nitrostyrene will create the phenylacetaldehyde, which might not be stable to polymerization under the reaction conditions. No P2P.
Another novel method for going from benzaldehydes to P2P's can be found in Post 333551 (https://www.thevespiary.org/talk/index.php?topic=11449.msg33355100#msg33355100)
(Barium: "benzaldehydes to phenylacetones", Novel Discourse)