An all new take at my add life function from my health bar datapack
Please Note: this is a plugin not a datapack it is built for version 1.20.1 and further of minecraft servers running paper spigot or bukkit

commands:
/addlife - this will add life to the player if they have at least {cost} amount of {item} in their inventory
/resetlife - this will reset the max health of the player who runs the command to {base health} NOTE: only oped player or players with the permission lifeline.resetlife can run this command

all values in {} are configurable in the configuration file cofig.yml

please be sure to inform me here if you come accross any errors or glitches in this plugin so i can work to fix them, Enjoy!