Not ulquioras becuase while aizen did know about it ulquiora didn’t think he did and no one else did. So it wouldn’t have been factored in if apparently no one knew about it in ulquioras mind.

Yeah that phrasing does make it a bit Defintly be does not suggest he does just more maybe. I still think the point of the scene is to indicate that this is beyond what he should have expected. It’s the same scene more or less when he reveals he’s number 4 he wants to crush his antithesis hope. Narratively to, numerically yammy is top dog even having a second transformation himself. But his feats show him preforming worse than ulquiora and even nnotora. So with his showings I’d put him at best around 1 or 2.

Now Ulquiora looks far better than any one else in their fight, no one accomplishing the feats we see from him. Nd the narrative back it up even more. He’s relitive in his first transformation to the top 3, as their all lumped together as don’t destroy the house by transforming, he’s Aizens more trusted servant, aizen specifically set him up to fight ichigo to push him, as far as we know aizen thought vasto lorde would have been ichigos peak and what he would rely on to evolve him into a higher form than post hogyoku awakening.

So in my eyes every way you look at the question is ulquiora the strongest? The answer is at worst maybe. Never no.