Datapack for limited item spawn in loot chests

Hi, new guy here, Playing on my server and trying to increase difficulty in various ways, one being Hunger/food. Right now Chests are way to op, in dungeons and in villages, as every chest has like 5-20+ of bread, apple/etc, so what I've come to is datapack might be my best solution to fix this, but have no experience in the making of such, could any help, or point me in a direction? 🙂