No that doesn't mean he was stronger than Luffy i think his level will be increased for script reasons if he hurts an emperor because even though he was in the new world for 2 years he didn't have to deal with a Katakuri or a Cracker or a Doflamingo.
How can he be stronger than Luffy who beat Katakuri an observational haki expert who can see the future?
On top of that Luffy underwent training with Rayleigh on the haki for 1.5 months, Rayleigh left him 6 months alone because he had already learned