I would say that comparing Rav Ovadia to R’ Akiva is silliness. We don’t compare ourselves to previous generations at all. We know that we don’t rate. “Im harishonim kemalachim etc”
So as far as comparing levels, one would rate people by their very own standards. I hope that even if we are unable to determine ourselves who is the greatest among the great ones, we should at least be able to tell who is great. To borrow an expression, who would at least be in the team photo.
Once you determine that, observe them and see who defers to whom. Because even if we can’t tell at our low level who is greatest, those who are in that sphere might have a better idea. So to follow through on your analogy of the sephardic gedolim, do you ever see someone like Rav Ovoadia consulting Rabbi Shlomo Amar? Not very often. But the reverse is a regular occurrence. The sephardic leaders are always consulting with Rav Ovadia.
Likewise, we may not be able to tell among the local rabbis who’s the heaviest hitter. But watch them. You’ll see they recognize among themselves who is on a higher madreiga. and who they consult with, when something need to be brought to a higher authority.
Lo almon Yisroel. Hashem guarantees us that he will put in the hearts of the people the wisdom to at least choose who their leaders should be. Can anyone of us know for sure? Maybe not. But HKBH loves his children, and he will guide them in a general way to find the right leaders.