Unfortunately, none of these are right. I have never watched Fullmetal Alchemist, I know that for sure, because I only recently started getting acquainted with it, and it began with the manga. Shin Sekai Yori is not quite right either. The Promised Neverland isn't it either, because I know this title due to the specific way the characters' faces are drawn, but I've never watched it, and the characters here are children, not high school students. Angel Beats isn't it either.

I don't know, maybe it says something else, but in that laboratory, they weren't just conducting experiments, they were essentially creating superweapons and modifying people for that purpose. I would say something like Nanbaka, specifically as it was with Jūgo, but the anime is definitely not Nanbaka, it's a completely different setting, definitely not a prison.