“Moins on en parle, mieux on se porte.” is made of two separate idiomatic phrases and is a way to build a (quite good) French equivalent to this expression. This combination is common, and even though it might not be considered a proverb or a saying, it sounds like one.

I would use the expression “moins de paroles, plus de résultats”, meaning “less talking, more results”.

A bit aggressive :”Au travail, sans phrase !”