Zetsu's feats are insane. Not even just that but he deflected TSO from Juubidara, impaled Rinnesharingan Juubidara, intercepted Base Edo Minato, outpaced KCM2 Minato & WA Kakashi and reacted to 1R Juubidara.

Zetsu's feats are impressive

But only enough to beat the real weakest member of the akatsuki sasori

Given, kakuzu was able to treat choji like a non factor and had a pretty even fight with kakashi

I think that puts him above zetsu

Zetsu kept up with 3 leaf jonin but ended up losing to chojuro

Kakuzu is stronger than Zetsu. Kakuzu can quickly teleport through earth element techniques and make his body hard, making him virtually immortal. This can be seen in Kakuzu and Hidan's battle against Asuma Sarutobi's squad. He also owns 4 elements of the elements in addition to earth. The fact that he couldn't evade the rasen-shuriken attack is the power of the plot that had to be drained to keep the main character and his friends alive. By this analogy, Payne (6 paths except Nagato) is also weaker than Zetsu, because he couldn't evade Naruto's USUAL rasengan and died,despite the fact that 6 paths use a lot of rinnengan potential.