Worry not; if you didn't get any answers last time, it's entirely acceptable to repost. After all, it's entirely possible that your question might not have been seen by the person who could provide an answer, or it was just a bad time for them, or any of a dozen Things That Go Off that are part and parcel of everyday life.

Anyways, onto your question specifically, you're in luck - I'm deep-diving for additions to my Medieval Armies Compilation, and I have for you a whole bunch of posts specifically related to mercenaries of the Medieval era. As always, should anyone have a proper post to make that answers OP's question, don't let me stop you!

u/AlviseFalier is the standout here, with four! posts on Medieval mercenaries, with special reference to Italy:

• "How were medieval mercenaries companies structured?"
• "I'm a young man from Florence during the 14th century, and I want to become a mercenary. What should I buy first? How do I sign up? What is life like for a mercenary? What would my friends and family think?"
• "I'm a young Italian lad seeking a more exciting life in early 15th century Italy. I hear mercenaries are all the rage, how would I go about joining some?"
• "Did mercenaries in the middle ages carry banners in battle? If so, did they have their own banners, or did they carry the banners of whoever hired them?"

For a late Medieval look, one cannot overlook the German Landsknechte, examined in detail here by u/sunagainstgold and u/hborrgg.