Which preposition to use in "gettarsi a capofitto sul/nel lavoro" to say "throw yourself into work"?

Question

gettarsi a capofitto sul lavoro

{or}: gettarsi a capofitto nel lavoro

The equivalent French expression "se plonger dans son travail" invariably employs the preposition "dans" corresponding to "in" in Italian. The same goes for "throw yourself into work" in English; you never say "throw yourself onto work".

A few bilingual dictionaries that I have consulted have it as "gettarsi a capofitto in ...". The thing is that I came across "gettarsi a capofitto sul lavoro" in an email message professionally translated from English -- and written in a colloquial tone. As such, I figured it was unlikely that a grammatical error like this would slip in.

Answer 1

As you can see on Treccani dictionary or Sabatini Coletti dictionary one says gettarsi or buttarsi a capofitto in qualcosa. So in this case, it would be

gettarsi / buttarsi a capofitto nel lavoro.

Preposition "su" used with verb "gettarsi" has the nuance of "above something". So, for instance, one may say

gettarsi sul letto

with the meaning of "on the bed", or, in a figurative way,

gettarsi sul nemico.