Ладушки-оладушки, Но всё равно советую опробовать, в основном командами не отличимые друг от друга
# 1H9L datapack by dangor
# 1hp mode
attribute @p minecraft:generic.max_health base set 2
scoreboard objectives setdisplay list 9lifes
# Scoreboard tablist 9lifes
scoreboard players set @p 9lifes 9
scoreboard players set @a[scores={death=1}] 9lifes 8
scoreboard players set @a[scores={death=2}] 9lifes 7
scoreboard players set @a[scores={death=3}] 9lifes 6
scoreboard players set @a[scores={death=4}] 9lifes 5
scoreboard players set @a[scores={death=5}] 9lifes 4
scoreboard players set @a[scores={death=6}] 9lifes 3
scoreboard players set @a[scores={death=7}] 9lifes 2
scoreboard players set @a[scores={death=8}] 9lifes 1
# Null lifes
gamemode spectator @a[scores={death=9}]
---
# 1H9L datapack by dangor
# Scoreboard 9lifes and death
scoreboard objectives add death deathCount
scoreboard objectives add 9lifes dummy
# Message reload and starting the game
tellraw @a {"text":"Datapack 1hp by dangor, score life to tablist","color":"aqua"}
Пример из дата-пака - Для обычной игры нужен был-бы несколько ком.блоков, а тут всё в 2 файлов
