No matter how you feel about the ship or these characters in general, the relationship Eren and Levi are important to note. He’s something of a fatherly figure to him, giving him advice and having obvious concern for him, even reassuring him when he feels guilty about Levi’s injury and the death of his squad.
It wasn’t always like this, however, and before Eren’s accidental transformation when he tried to pick up a spoon, Levi had clear disgust and uncertainty about Eren. The way he looked at him, called him disgusting, didn’t seem to care about kicking his tooth out, and how he called him out in anger both when Eren was terrified of getting his limbs cut off and when he couldn’t transform in the well, proved Levi was not particularly fond of Eren.
But as soon as he accidentally transforms and causes the squad to go on high-alert, Levi’s feelings clearly change. He protects Eren from his squad out of ‘tuition,’ and afterwards not only asks Eren how he feels, but gives him a father-like talk about how it wasn’t his fault that the squad acted the way they did, and how he shouldn’t be upset.
After that, there’s a clear change in his behavior when it comes to Eren. There are still times where he insults him, but one could say that’s just Levi’s behavior, considering he’s insulted Erwin and Hange in the same way, despite his clear trust in them. And other than these insults, he gives concern for Eren’s well-being. He continues to insist on nothing being Eren’s fault whenever he appears to feel guilty, even making jokes to make him feel better, while still making it certain how incredibly important he is to the Legion.
He goes from implying Eren’s lying about his loss of memory, calling him a lizard, staring in disgust at him, and telling him he’s basically useless for losing his power, to legitimately caring for his well-being and giving him words of wisdom to build up his confidence. He ultimately becomes his father figure in the absence of his real father. He’s done something of the same to Mikasa, as well, leading to the idea that maybe he isn’t as horrible with kids as one would think he is.
It should be eye-opening to see how he deals with a squad full of teenagers, and especially to see him constantly around Eren in a way we haven’t seen since his squad was killed. It will be more obvious to see how their relationship has evolved when you compare the two squads side-by-side, and how Levi deals with Eren now versus how he dealt with him then.