I don't see why it has to be taken so negatively. Of course the current situation is straining for Koto, but she has been unhappy and ashamed with her own helplessness from the start. Even if it's difficult, actually changing, with someone who keeps pushing her past her (very low) limits, goes in the direction she has always been wishing for ever since she cut ties with Mariya.
There is also the fact that none of what Koto is forcing herself to do right now is actually excessive in any way. Making an effort to go against her lazy nature and do normal things isn't bad.
With enough time and opportunities (such as the cultural festival mentioned at the end of the chapter), Koto might eventually be able to do things proactively without it being such an effort that she needs someone to keep her in check.
I'm not disputing the fact that Koto's desire to be self-sufficient is or isn't a noble one. I think it's worthy of praise to try to improve yourself to be the best person you can be. In fact, both Koto and Mariya believe this fundamental fact.
However, if it is clear that they both agree on this one point, why is it that Koto still feels anxious about this "self-improvement" relationship with Mariya, to the point that the "flunked-a-grade" crew all resoundingly noticed a concerning change in Koto's behavior?
Now, it's possible that there was some sort of traumatic experience that would cause Koto to feel distanced from Mariya, but with the current information at hand, I think it comes down to something more rooted in their relationship. They have lost sight of the goal, the desire for Koto to become self-sufficient, and have turned toward a new metric: avoiding disappointment.
Mariya has, in my eyes, developed into some sort of helicopter parent for Koto. She has an almost dictorial way of "babying" her, even to the point where she creates an over the top self-help calendar that instructs Koto's development schedule over an entire month. In essence, she wants the best for her "child", much like how the "child" wants the best for herself as well. The issue lies in the fact that in trying to accommodate as much as possible to what she believes is best for Koto, she loses sight on what actually is good for her. This is the main reason why I called Mariya "yandere". Often times, yandere characters show intense admiration to their object of affection, to the point of misery for said object of affection.
On the other hand, Koto feels an intense urge to not disappoint what is essentially her closest friend. She puts on a painfully obvious facade of "put-togetherness" to her friends and when she finds that there are no drinks to provide for the others, she freezes up entirely, unsure of what to do. She is essentially fearful of failure, and even the presence of Mariya is the dreaded prospect of being placed under another expectation that she could potentially undercut.
While it is true that nothing seriously damaging has happened as of yet (though, one could argue that Mariya was a major reason why Koto flunked a grade), the point of contention is that their current relationship is not sustainable at all, and could potentially spiral into another bout of intense depression for Koto. That being said, this is all speculation, and it is possible, even likely, that the mangaka will develop the story differently from what I've stated.