I would agree if manga didn't display the complete opposite.
1st exchange: Smoker goes around Vergo for a Jitte attack -> vergo dodges -> Throws a kick -> Smoker blocks his kick -> Vergo tries to attack with the bamboo -> Smoker dodges and throws a punch -> Vergo laid out on the floor bleeding.
2nd exchange shown is Smoker again hitting this dude and bloodying him up.
Vergo is never gone be able to tank clean hits from Smoker like nothing happened let alone combo punches.
As for going from trying to beat Vergo and then switching to getting Law's heart, disagreed on that. If it was about just whooping Vergo's ass, Smoker would've gone that long ago. The issue was retrieving Law's heart, which Vergo could just destroy within a second the moment he senses hes about to lose, similar to Ceasar who thought he was stabbing Smoker's heart. His objective from the get-go was to get the heart. Hence why Law states, the deal is done. And then later states about how Smoker being nice to him resulted in good karma for him, related to their hearts.
Never understood lowkey where folks got the switch of hearts things from, never implied by Smoker or Vergo or Law. Even Vergo simply mentions Smoker not fighting like himself by expanding the Smoke. The fight starts in chapter 684, and then in 685, we see that Smoker was already fighting by expanding the Smoke, unlike himself. Which continued on for 5 more chapters after that.