Spoiler: Just to be safe, since I reference a lot of supports...
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Lorenz has a massive one, where Ferdinand really doesn't. Lorenz can't understand why the girls would be bothered by his constant invitations to eat with him, he believes himself destined to be the leader of the Alliance even though that's really Claude's job, he has a habit of trying to call attention to his own perceived greatness and superiority ("I am Lorenz Helman Gloucester, after all!" - hell, he still does that in many of his A supports), and he really feels that nobles are inherently superior to commoners in a number of ways. With Ferdinand, on the other hand, his ego only really extends to his competitiveness with Edelgard - he wants to be seen as her better, specifically, but no one else's. So when he talks about the responsibilities that being a noble brings him and others, I buy it; it doesn't come across as him being arrogant about his birth status, it comes across as his genuine belief (because it of course is), and he actually does act accordingly. He's occasionally a bit oblivious, such as when Lindhart's sarcastic mockery of his beliefs about nobles went right over his head, but that doesn't come across as a flaw like it does with Lorenz but as an endearing trait, where the weighty responsibilities that he feels nobles have is such an ingrained part of his mindset that he misses when other people don't think that way if they're not being blunt about it.
At the end of the day, Lorenz actually does believe things quite similar to what Ferdinand does, but because those beliefs are all wrapped up in his oversized ego as well, he comes across as much less genuine about them when he does speak about them, so it's more a surprise when he actually acts on them later. It's what makes Lorenz feel stuck-up, where Ferdinand really doesn't. Lorenz will actually say that some things are beneath him because of his status, where I don't believe Ferdinand ever does. It's arguably fair to say that means Lorenz had more character growth that he needed than Ferdinand, but I think it's also fair to see that as Ferdinand just being a better person than Lorenz. And it never quite feels to me like Lorenz fully gets over himself by the time you're seeing his A supports - he comes across much better by then, but that ego and sense of superiority is still there, just tempered by him more openly showing his better qualities than he used to and having a stronger foundation of friendship with the others. Granted, I've yet to see the ending of Golden Deer (on chapter 18 now), so I technically don't have the full view of him yet, but his ending still needs to take him a decent extra step for me to see his growth as fully overcoming his major flaws.
And it's not like Ferdinand doesn't have to grow at all - his support with Edelgard in particular is notable for this. Not only does he have to get over his competitiveness with her and accept that yes, she is just a better warrior than him, but (since you have to side with Edelgard to get their A support) he also has to figure out what he's going to do in a world where the nobility is going to be abolished as well. And his answer is that he's going to try and help Edelgard find a way to bring what he feels is the reason the noble system created new leaders each generation to the masses: the way it educated noble children. He has a serious talk with her about the need to bring some form of widespread education system to everyone if they want the Empire to thrive as the meritocracy she envisions, and even she recognizes that he's clearly given it a lot of thought, and it's something she hadn't considered before. Coming from a person who on the surface would seem to believe that nobles are just superior, that's a wonderful capstone to his character to me, him helping to figure out what elements of the nobility system need to be brought to everyone if it's to be abolished, and identifying that rather than anything superficial or the wealth that noble houses have. It makes him end up feeling to me like a genuinely thoughtful, actually noble (and not in the status sense) character, in a way beyond what Lorenz ever quite reaches from what I've seen - he's fully ready to give up on the noble system that is so central to his character, as long as what he feels is the important part is preserved and passed on to everyone.
That is why I like Ferdinand better than Lorenz, personally.