I think for starters, we should probably take Bellonci's bio on Lucrezia with a more careful approach. It's such an outdated book, Lucrezia clearly was not the femme fatale that Dumas and the liked had presented her to be, but she was not an innocent, sweet girl who was a mere victim of the men of her family either. I believe Bradford's view of her is a little closer to the truth. So you know, Lucrezia on this book makes no sense to me whatsoever.
Now with Cesare, what can I say? It mostly falls flat and dry to me? I do understand he could be a cold and utterly ruthless and pragmatic man, all qualities that drew Machiavelli to him, but this icy almost robot-like portrayal of him is always a stretch and a disappointment to me. While reading this I thought to myself: He could have never gained the amount respect and loyalty and affection he got from his soldiers and the people of the Romagna if he was truly like that. This was a man who clearly had an enormous amount of carisma (that ran in the Borgia family btw) and he was very much a Spaniard, with all the hot blood clichés. He fought bulls in the arena, he was always accessible to the people of his duchy and he was very patient at listening to their complaints. That's was so fascinating about Cesare Borgia. He was in many ways a typical cinquecento man, with all that ruthlessness, but he was also very different in others ways from his contemporaries and he occasionally could be disarmingly charming and warm when he wanted to be or with those he respected or cared for.
And that's what this book failed to bring to me. I felt nothing for Cesare while reading it and that just a bad sign. The author's claim of "accurate fiction" doesn't make me comfortable either tbh. So you know, I didn't hated it, there are worst fiction out there for sure, but I didn't loved it either. It was just...ok.