I think people misread Claudia when she said Lestat was her favorite during the seance in ep 3x06. It's not about any partiality towards Lestat.
In her words: "I liked him better. He knew who he was. You're not even my maker, you're not even my blood. That's my maker." She's pointing out that the one who carried the weigh of making her is Lestat. And Lestat took that title even knowing what that would bring, he knew who he was.
Lestat bore the identity of "maker," even when he knew it would mean becoming the object of Claudia's hatred. During Claudia's turning, Lestat is the one who physically performs the act of making her a vampire. Louis is present, and in fact the entire situation exists because he begged Lestat to turn her, but when the irreversible moment arrives, Louis turns away. He can't watch.
Louis wrestles with his own agency. He wants wants to see himself as good, and that internal conflict leads him to distance himself from the uglier parts of his own decisions. Louis is the one who insists that Claudia be saved, despite Lestat's repeated objections that turning a child is a terrible idea. In that sense, Louis is morally implicated in her creation even if he is not literally her maker.
He feels this need to save her due to his own guilty conciousness and as a clutch for his own sense of moral identity. When Claudia confronts him in season 1 as to why he didn't take her to the hopsital, Louis responds with "you were barely breathing" , Claudia returns that by saying "But i was breathing!". She's exposing that there was still another possibility, however uncertain. Louis never allowed that possibility to exist.
His impulse to save Claudia is undoubtedly sentimental, but it's also bound up with his own unbearable guilt. He's watching an innocent child die because of events he's connected to, and he cannot tolerate that reality. Turning her into a vampire becomes a way to undo the unbearable fact that she is dying. Her turning was never about her, the decision itself was not centered on Claudia's autonomy.
So that's why when she says"That's my maker," she's not absolving Lestat. If anything, she's assigning responsibility to him and she's challenging Louis's tendency to avoid claiming responsibility for choices that he nevertheless helped bring about. In her eyes, the one who actually crossed the line, accepted the burden, and lived with its consequences was Lestat.
She's denying Louis the ability to occupy the moral space of the loving father while distancing himself from the irrevocable act that made her what she is. Lestat, for all his flaws, cannot make that separation. He is her maker.
And I see arguments of people mentioning how Claudia saying "you're not even my blood." makes no sense considering that in season 2, she initially refuses to make Madeline using Lestat's blood. But I think that comparison gets lost to the point Ghost!Claudia is saying.
When Claudia tells Louis, "you're not even my blood." She isn't glorifying him in any capacity, but the one who took responsibility for her making wasn't Louis. She's saying how Lestat carries that burden, weather she loves him or hates him.
Ironically enough, that same idea was reinforced in season 2. Claudia initially rejects the concept of using Lestat's blood to make Madeline because she doesn't want Lestat to have any claim over the life they're creating. But later on in the episode, she does use his blood, and Madeline reminds her that the blood that is going to make her also made Claudia. In other words, Lestat's blood is part of who she is.
Again, this scene isn't about Claudia embracing Lestat over Louis or declaring him the better parent. It's about forcing Louis to confront a truth he's spent years distancing himself from. He begged for her turning, but when the moment came, he couldn't even watch. Lestat was the one who accepted the role of maker and all the consequences that came with it.