And nothing suggests Trebol's not as strong as Vergo, Pica, and Diamante either. It makes no sense for him to be that far weaker than them.
You do know that the physical abilities of the M3 themselves are also "far beyond any normal human's", right? Robin's statement may not be implying Trebol is as strong as the M3, but it's definitely implying he's a monster in his own right. He was also suggested to be a monster a second time when Robin referred to Level 4 as the 'Battlefield for Monsters', which was where guys like Doflamingo, Trebol, Luffy, Law, Kyros, and Diamante were fighting at the time.
Yes, with utmost confidence I do think he could keep up with those guys. Unlike you and some others I don't think Trebol's weaker or at least dramatically weaker than the rest of Doffy's Chief Officers.
I already acknowledged that Trebol didn't actually show any feats comparable to Pica, Diamante, or Vergo during Dressrosa, but that's on Oda. And I stand by my point that nothing in the story suggests that Trebol isn't as strong AP-Wise as the other Chief Officers just because the author didn't let him show off in a proper battle like he let the other Officers do. If he was, then Doffy wouldn't have trusted him with the important job of guarding Sugar. He could've easily given the task to either Pica or Diamante.