لَمْ نَرَ كُلَّ النُّجُومِ.
We did not see all the stars.
لَمْ نَرَ نَجْمًا وَاحِدًا.
We did not see even one star.
The first naturally denies universal coverage: some stars may well have been observed. The second explicitly denies the occurrence of any single observation. These sentences are not interchangeable.
Changing “not everything” into “nothing” expands the force of negation without justification. The placement of negation and quantifying expressions must be established before describing the wording as concise or emphatic.