I tried following the advice in this thread, and it does work for the wooden pickaxe example they give, but I can't disable a lot of the armor recipes this way. As an example, here is my json for the iron chestplate (it's in data/mymodid):

{
  "type": "minecraft:crafting_shaped",
  "pattern": [
    "X X",
    "XXX",
    "XXX"
  ],
  "key": {
    "X": {
      "tag": "forge:ingots/iron"
    }
  },
  "result": {
    "item": "minecraft:air"
  }
}

Some of the armor pieces work just fine, but this one doesn't work.
I've also tried

{
  "type": "minecraft:crafting_shaped",
  "pattern": [
    "X X",
    "XXX",
    "XXX"
  ],
  "key": {
    "X": {
      "item": "minecraft:iron_ingot"
    }
  },
  "result": {
    "item": "minecraft:air"
  }
}

I've also tried both of them at once. I also tried

/datapack disable "mod:forge"

that also had no effect.

Does anyone know how to fix this?

Here is a list of the items that I can override:
iron helmet

iron boots

golden chestplate

golden helmet

diamond leggings

diamond boots

diamond helmet

which leaves the ones that don't work:

iron chestplate

iron leggings

golden boots

golden leggings

diamond chestplate

 

Attached are the jsons I'm using.

 

 

chainmail_boots.json chainmail_chestplate.json chainmail_helmet.json chainmail_leggings.json diamond_boots_forge.json diamond_boots_vanilla.json diamond_chestplate_forge.json diamond_chestplate_vanilla.json diamond_helmet_forge.json diamond_helmet_vanilla.json diamond_leggings_forge.json diamond_leggings_vanilla.json golden_boots_forge.json golden_boots_vanilla.json golden_chestplate_forge.json golden_chestplate_vanilla.json golden_helmet_forge.json golden_helmet_vanilla.json golden_leggings_forge.json golden_leggings_vanilla.json iron_boots_forge.json iron_boots_vanilla.json iron_chestplate_forge.json iron_helmet_forge.json iron_helmet_vanilla.json iron_leggings_forge.json iron_leggings_vanilla.json leather_boots_forge.json leather_boots_vanilla.json leather_chestplate_forge.json leather_chestplate_vanilla.json leather_helmet_forge.json leather_helmet_vanilla.json leather_leggings_forge.json leather_leggings_vanilla.json netherite_boots.json netherite_chestplate.json netherite_helmet.json netherite_leggings.json wooden_pickaxe_forge.json

I forgot leather; boots and helmet work, chestplate and leggings don't.

https://github.com/Lukerd-29-00/balancedarmor

where do I put them instead?

I figured it out, never mind. I moved the files ending it _forge into data/forge/recipes and the ones ending in _vanilla into minecraft/data/recipes, that did the trick. Thanks for pointing me in the right direction!