Firstly Hisoka didn't exactly outsmart razor, he just made the return of a ball with a rubber element aura, even i would've thought of something similar on the spot. Not alot of insight. And secondly you saw the physical strain Razor was causing to all 3 of them when they even combined to stop the ball. In terms of raw power Razor could probably beat Hisoka, but the utility of Hisoka's skill is where the real shady jump in power comes from. It's unpredictable nature makes him something to watch out for, being able to hold Gyo on at all times is probably in the base requirements of beating Hisoka. Hisoka is strong. but is he as strong as the bigger tier of opponents? Not particularly.
That's what I call outsmarting, Razor didn't think of it, same as when he waited for the ball to fall and Hisoka caught the ball before he could do anything. I don't understand why Bungee Gum would not count as Hisoka's power, he was the one who created his Hatsu and use it very well, he thought about the numerous applications, nobody has a power like him and nobody could use it like him. True that it was hard for them to stop his ball but it's because Gon was not eliminated, he wanted to face Razor, it deosn't change that Hisoka returned his last attack with his Bungee Gum despite his two broken fingers.
I disagree with your opinion that maintaining Gyo is enough to beat him, as he said against Gon, he hides it only when his opponent is not on his guard(and being on his guard in a fight to death is crucial), Bungee Gum is not an ability only useful for tricks, to fight against Hisoka when serious would be very annoying, again I will use Hisoka VS Gon as an example the only fight where he really took the initiative to attack for real, he can stick it to his members and with only one hit you are trapped, once he used it he can control the gun remotely, in his last fight we learnt that he can use it even on his legs, the applications are endless, to not be caught by Bungee Gum you must dodge all his attacks.
By raw power do you mean Aura volume? Though I think he is most likely superior there is no way to confirm that, same for physical strength since Hisoka is physically stronger than even the bulky Franklin who is an Emitter like Razor, raw power is not enough to win in a Nen battle anyway or the best fighters would have only been Enhancers.
Hisoka would've probably lost against any of the Chimera Ant Guards. (considering how a strike team wasn't strong enough to wipe them out and it took poison to kill majority). Meruem post and pre rose would've beaten him.
Of course, the Royal guards are stronger than all the human characters who appeared so far.
As for the Chrollo vs Zoldyck face off. It's because it was a plot device that it was important to pay attention to. Yeah the author didn't want anyone to die in that fight, obviously but the point made is still clear. Here is a character who can hold his own against two well known assassins in the Hxh universe, who are coming at him with the intent to kill. Obviously the intent to kill =/= using their max power, but still two Zoldycks at once? That feat is impressive in of itself. As you said: Illumi, Zeno, Silva are in the same ball park. even without 100% effort. The two of them on Chrollo at the same time with a mission to kill him? A mission that would probably be easily accomphlished by sacrificing one of their own? Chrollo is definitely stronger. He fought Silva 1vs1 when he was younger and survived, and he has the ability to kill the old head of the Zoldycks in a 1 one 1? So far the only impressive thing we've seen Hisoka do is manipulate the phantom troupe as a whole, and face Razor.
Vs Chrollo fighting two Zoldycks at once and holding his own while lacking the intent to kill, only to fulfill conditions to activate his nen ability.
Chrollo was very impressive indeed, but it's not only because he is that strong that he survived, it's because he was only focused on defense, he was not trying to kill them because he was pressured by two opponents of his caliber, had he been on the offensive it would have been different, his defense would have dropped and there would have been openings to kill him. He didn't show his cards, what was really impressive was to see him clash with Zeno who was trying to kill him, while still being able to follow Silva. In 1VS1 him winning against Silva or Zeno is not certain(though I personally think that he is stronger than Zeno but the fight would be very difficult anyway).
About Silva's attack, after rereading the fight I am even more certain that he didn't tank it, he must have dodged and used Ken or Gyo to protect himself from the explosion or used an ability
Zeno's Dragon Lance would have been enough to break his guard, we can agree that Zeno and Silva's power are similar, there is no way he simply tanked it. The problem with Hisoka is that he has more hype than feats, he is praised by strong fighters and has never fought someone of his level in the manga, if you agree that Zeno, Silva and Illumi are in the same ballpark, why do you think that Hisoka is not when he is clearly at Illumi's level?