yeah you said all of this well. the “incident” can be whatever it wants to be, seeing the characters grow (female teacher) or be acknowledged (ML and friends) or show trust to others (male teacher) makes this arc imo really good and that’s the important part
and the last part is huge for me, actually seeing adults acknowledge and learn from their wrongs to better themselves and help the younger characters (▰˘◡˘▰)

The reason was anti climatic, but the end was great. As student, or children, seeing a teacher or adults admit their mistakes and ready to change is much bigger than some revenge or non resolution bullshit.
It felt like what they did was not wrong, and they can keep being friends aithout the expectation something might go wrong in the future.
I don't know how to accurately say this, but it actually felt like they have adults who truly understand and trusts them to be the best of their eir behaviour as boys, or man. Regardless of the past experience.