Obito had half of his body made with zetsu spores made from the Mazo tho more DNA than anyone. Naruto is basically like Danzo a Hashirama arm. He couldn't use mokuton but his arm did/could.
What makes you think that the quantity of cells that Naruto received isn't enough?
Where did you see in the manga someone talking about the quantity of Hashi cells needed to awaken Mokuton?
Your reasonning is a theory.We don't know if the quantity of cells received has something to do with the ability to use Mokuton.
Are you denying that Naruto has all what he needs to use Mokuton?
Have you seen the chapters where it shows how Naruto's chakra reacts to White Zetsus cells (Hashi cells)?