Actually the largest influence on Communism was hardly The Prince whether Stalin kept it on his nightstand or not. The rejection of Christianity by some and Judaism by others in Europe was what gave rise to Collectivism and Messianic Humanism which depended on the naive notion of the new man devoid of self desire as the Godhead.
The most influential book to my mind’s eye in Machiavelli’s era was written in Paris by an Englishman named Hobbes. But to be fair, The Prince was unique at the time because it was a roadmap not so much for realpolitk but for a new ruler versus one who had inherited power....something fairly revolutionary for the time...a little nuance that makes it immune to your casual dismissal with all due respect.
I don't think it was just the rejection of Christianity but the perversion of some aspects it. Marx's theory of history looks to me like a secularization of the Christian heresy of millennialism.
The most influential book to my mind’s eye in Machiavelli’s era was written in Paris by an Englishman named Hobbes.
I agree. But you didn't say if you thought Leviathan was a positive or negative influence. I think Hobbes book has been one of the most damaging to liberty ever written.