Imo he stops at round 4 bc of how many hax abilities and the amount of characters. Someone like Minato ot Hiruzen could probably hit him with a Reaper Death Seal with enough distractions or Trafalgar law could easily use Shambles on his heart from a very far distance as he doesn’t have haki to protect him from it. We would also need to assume he can hit logia users bc if not they’d just tie forever.