Ehhhhhhhhhhh
Even Buffy was hit and miss in that regard, especially in the first season. Xander, Oz and Willow join Buffy on her hilariously dangerous escapades and don't seem to really care all that much. It's not until they start going into their respective main arcs that they start feeling the "weight" of their actions. Death is treated pretty flippantly too, barring a few important cases. Principal eaten alive but students possessed by ghost hyenas? Meh. Students murdered by bad guy of the week? lol. People seem to die every week and it barely matters and it's a serious low point of the show. On the other hand, when the show hit, it hit hard. Buffy's development is godlike, and lot of what you said applies to her (and arguably her alone ). She is straight up unrecognizable from season 1, but in the best way possible.
Honestly, P3 is pretty close to Buffy. Similar structure, similar cast of high school students and misfits brought together by a common goal (Junpei IS basically Xander, but he has the benefit of hitting the ground running unlike Xander who is garbage for about 20% of the show's runtime). I also think P3 had a fair amount of moments where the characters were overcome with despair, even post character development (moreso in the movie), but it's been a while since I played so I can't be too sure.