How do i make a loot table replacement?

i tried to make a custom loot table for zombie but for some reason this doesnt work. i followed multiple tutorials, the datapack structure is data/minecraft/loot_tables/entities/zombie.json. the pack mcmeta format is set to 1.21.3 which is 57, and i dont get any warning on the logs. i also tried using an alternative, simpler loot table: 
  "type": "minecraft:entity",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "minecraft:item",
          "name": "minecraft:diamond",
          "weight": 1,
          "functions": [
            {
              "function": "minecraft:set_count",
              "count": {
                "min": 1,
                "max": 10
              }
            }
          ]
        }
      ]
    }
  ]
}```
but i still cant find the issue.