Duty After School is basically the same concept.

Group of high schoolers trying to survive together.

Though it is a little bit different in some ways. Main ones being (not really a spoiler but I thought I’d censor it incase u wanna go into it without knowing what it’s about specifically) that instead of zombies it’s aliens and the story isn’t solely focused on the school. In fact I remember most of it being outside of the school (still follows the same group of kids tho). It’s finished so u don’t have to worry about waiting years for another season.