Son sat, thuy chung: a Keep Inventory enchantment

Son sắt, thủy chung: A keep inventory enchantment
I see other "keep inventory" datapack work by turning keep inventory to true (and remove item from player inventory), and broke when immediate respawn. I want my datapack to work without changing anything and should work if anything changed, so I create this.
The enchantment can be found in treasure chest or trade with villager.
(I try only saving player's inventory when dying but death animation happend as inventory drop, so when command executed player's inventory has already empty. So I change to save when player's inventory update)