I don’t think Machiavelli was being satirical I think he just really wanted someone to unify Italy because he saw how being a bunch of small states constantly fighting each other made Italy weak enough to be influenced by other non Italian powers. In his lifetime, southern Italy was ruled by a Spanish kingdom, and most of northern Italy was ruled by the Holy Roman Empire which was an elective monarchy but all the electors were German. One point of evidence that it’s not satirical is that there’s a large focus on it about not relying on mercenary forces, and emphasizing the importance of a state controlled army made up of citizens. He wrote another book prior to the prince that is more focused on warfare (on the art of war), and this book has a lot of similar ideas in it regarding the military being elaborated on further than in the prince. If it was satirical it doesn’t really make sense for him to bother with putting his actual thoughts on military organization in it. It’s likely it actually was meant to serve as a guide for Italian nobility to unify Italy.