With the hint of Nodoka's past more and more, it is clear she doesn't hate Mai. In fact, to hide that feeling she has to use the word hate. Although it's apparent that Nodoka wanted to be just like her sister. It makes you wonder know if that pressure is more self inflected. Just look at her mom. Sure, when she comes looking for Nodoka she seems harsh towards what she thinks of Mai. As Mai points out, she is quite invested in her performance and success. In fact, you imagine for Mai and given what we know about her mother, she is jealous of Nodoka to having a caring mother.
Though for Nodoka seeing that problem did more harm than it did good. The sister that she could never catch up to was having success in ways that Nodoka could never do. Luckily, Sakuta is around. While he doesn't have any feelings about Nodoka he can tell how much Mai loves her sister even if she can't be up front about her feelings. Hell, he can empathize with her because he has Kaede. Of course, the differences in his situation with Kaede is way different from Mai & Nodoka's situation.
The scene where Sakuta shows off the letters that Nodoka sent to Mai really illustrates how much Mai loves her sister. As we know with Mai, she had a bad relationship with her mother, and we don't know what she thinks of her dad. Nodoka praising her and having a sister like that probably meant a lot more to her than she lets on. As Nodoka admits in the past she wanted to be like Mai more than likely, it is safe to assume her mom wanted to make that dream come true. Though not being as talented as Mai made it harder. Makes me feel that her mother talked about Mai to try to push Nodoka to make her dream come true. With all that said, Mai's dream is sound because if you want to make your mom proud, do it in a way you want. Don't try to be like Mai.
We're learning more about Sakuta's family situation. It's good to see bits of improvement from Kaede at least willing to try different clothes. Though it seems the mom's situation is much worse than one could imagine.
While the emotional impact of the scene between Mai & Nodoka executed perfectly. Why this all happened felt off. It makes sense that Nodoka wanted to be like her older sister. Basically, acquired the blueprint of her body in a type of quantum teleportation. Thus, when she realized she didn't have to be like her older sister, everything reverted. It's just felt very tacked on at the end and it felt off.