Yeah, Sanji didn't quite break Blueno's Tekkai, but he almost did it, and he needed quite some momentum to achieve it. Then he went on to do the same to someone more than twice as strong in less than a few hours which can't be possible without some kind of power boost. Sanji didn't have a change of mindset, he was determined to save Robin all along.
Zoro also confirmed with Kaku that he has gotten far stronger since their first meeting so it wasn't just about mindset either. No training session happened b/w EL and W7.
It is possible though, Sanji´s attacks had more momentum in EL since he was jumping around, you also don´t have any idea in proficiency regarding Tekkai, and Blueno was nearly knocked out, whereas Jabra was hurt once, but otherwise only knocked back without any hint of breaking Tekkai.
Regarding Zoro
He literally is referencing the change in mindset, even Kaku underlines and knows that was not Zoro´s true power in Galley-La, and then references Zoro´s anger.
Has nothing to do with physically being stronger, but mentally a completely different fight.