I just hope the teacher won't end up with the student
And before anyone asks why or disapproves of my opinion, if this manga wants to tackle serious topics, it shouldn't present a student-teacher relationship as something acceptable, because it's not
I've had a few days to think it over, and here's where I ended up.
Most of the time, student-teacher relationships are a bad idea. The teacher has authority, the student does not.
However-
This is not all of the time. There are exceptions. And sometimes, the heart wants what it wants. Like you said, manga can use fiction to tackle serious topics. When student-teacher romances are presented as natural, it doesn't feel serious. It feels like wish fulfillment. The exceptions though; the idea that the teacher has authority might not apply. They might not have the student in any of their classes, or they might know the student outside of school as a family friend. The student might be the person driving the relationship, putting pressure on the teacher. Or they might be feeling mutual attraction, neither one putting pressure on. And they might both understand that nothing can happen until one of them graduates.
There is always the age-gap question, but here I think that the age of consent is a range rather than a concrete number. One person could be aware enough at 16, another at 25. It's a difficult question to navigate at this age, but not impossible.
Sometimes stories with this plot are just trying to depict pedialyte. Other times, they're trying to explore real issues. I don't know which this story is, yet. I won't make an absolute judgment. I won't make a categorical moral judgment, just a hypothetical one.
Even if this story presents an awkward and morally questionable ship, that could be the point. Not wish fulfillment, but "oh no they are going there."