"Edit" Vanilla loot tables

[prisma gyro]

So I'm working on something that I need to be able to override Vanilla loot tables however I know this isn't possible so I'm using scripts to do this but. Any way I do it doesn't work can someone Tell me what I'm doing wrong maybe it's a simple fix
Here's the code

import { world, system, ItemStack } from "@minecraft/server";
world.afterEvents.playerBreakBlock.subscribe((dat) => {
let block = dat.block;
let namespace = block.typeId;
let player = dat.player
let itemstackBefore = dat.itemStackBeforeBreak;
let itemstackAfter = dat.itemStackAfterBreak;
let item = block.dimension.getEntitiesAtBlockLocation(block.location);
const Block_handle = {
"minecraft:dirt": () => {

  for (const entity of item) {
    entity.kill();
    let item_dirt = new ItemStack("better_mechanics:dirt_powder", 1)
    block.dimension.spawnItem(item_dirt, block.location)
  }
}

}

Block_handle[namespace]?.()
})

I also tried using If statements Also didn't work

[prisma gyro]

Well I'm gonna try to figure this out if anyone does figure out what's wrong then don't hesitate to ping me

[long flint]

world.beforeEvents.playerBreakBlock.subscribe(e => {
    const {player,itemStack,block} = e;
    if (itemStack == ............) { // your condition
        e.cancel = true;
        system.run(()=>{
            block.setType('air');
            block.dimension.spawnItem(new ItemStack("id",1),block.center())
        })
    }
})

[long flint]

you can use BeforeEvents so you get to handle the case before the server actually registers that the player breaks the block, you can before the event so the block breaking doesnt get registered, and you use system.run to wait for the tick and set the block to air to break it without dropping the item, then you manually spawn the item at the block location

[prisma gyro]

Thanks Guess I was overcomplicating it