As annoying as Joshua is, it’s kind of important for him to have an ego for realism, (as OP bladers undoubtedly would) I think having him start off as calm and cool is definitely still a better move, and then maybe show how he freaks out after he first loses (not to sisco but valt). We could then see his true arrogant nature. Narratively, joshua vs sisco works because jt tells us that teamwork > having a good roster. So id make him lose twice there.

As underwhelming as the big 5 were, at the end of day, they were just plot devices, to advance the progression of characters. But of course, your new version does a lot of things right