How should I approach making bosses

I’ve been wondering on how I should approach making bosses for a multiplayer PvE game. Originally my plan for the game would just to be make it singleplayer but that wouldn’t recieve well on Roblox. It’s a story driven combat game with cutscenes and I want it to be possible to fight bosses for one person and another person can be fighting the boss. I understand that if I handle this on the server once one person kills the boss they kill it for everyone and making a boss for every single player would be laggy. I’m not sure if other games have done this so my question is how should I make chronological story bosses for each client to fight throughout the story in a multiplayer game?