I am trying to create a minigame map on bedrock version of minecraft and I need a way of detecting death

Solution 1:

You could create a dummy scoreboard connected to a pressure plate at the persons spawnpoint. Then you could then have another command that teleports them to where you want them to technically appear after they die. This pressure plate and command could be in an enclosed bedrock space outside of the map. The command would also target the nearest player to the command block.