I don't disagree with you storyist, since every dog truly is different. But your post made me chuckle because I had a 50% rottie/X who was a pediatric neuter. He was a heavy marker and absolutely took "offense over what he considers an insult to his pride" - that is such a perfect description for his ornery nature towards dogs.Admittedly my experience is with Rottweilers, but I disagree that neutering doesn't change anything except ability to reproduce. There's a pretty good likelihood, particularly done young, it will mitigate sex-based behaviors such as marking and leg humping. Most times a neutered male isn't as likely to take offense over what he considers an insult to his pride, so to speak, as an intact male. That said, some males seem unaffected. Neutering a dog doesn't have the pretty sure and pretty substantial effect gelding does on a stallion.
That said, there is an anecdote for every case out there! I agree with everyone that neutering, in itself, will likely not help OP's dog calm down.
I think a lot of anecdotal experience is just chance and correlation. My still-intact 3 yo male did calm down more at around 1 year of age. If I happened to neuter him them, why wouldn't I believe neutering helped him calm down? At around 1.5-2 years of age I dropped him from 5.5 cups a day to 3.5 cups a day because he refused to eat, even though he had been eating 5+ cups for all of his life so far. If I had neutered then, would I have said that neutering resulted in a drop in metabolism and appetite? It's just too easy to pin behavior change on something obvious and visible, like a surgery, rather than on something we can't see - the constant chemical changes happening in a dog's body and brain and they mature.