Nothing stackingSolved
I've checked the JSON set to 5. As well as reloaded plugin and server with no change. 
everthing is stacking except weapons
Not on my server unfortunately. I have it set to x5 on each category besides weapons and I'm getting vanilla stacks 

Merged post

{
  "Settings": {
    "DefaultStack": 0,
    "NewCategoryDefaultSetting": 0,
    "StackHealthItems": true,
    "CategoryDefaultStack": {
      "Ammunition": 5,
      "Weapon": 0,
      "Attire": 5,
      "Misc": 5,
      "Items": 5,
      "Construction": 5,
      "Component": 5,
      "Traps": 5,
      "Electrical": 5,
      "Fun": 5,
      "Food": 5,
      "Resources": 5,
      "Tool": 5,
      "Medical": 5
    }
  }
}
You didn't increase the stack sizes x5, you literally set the stack sizes to five.
But in any case, for the config file to take any effect you must delete your data file so that it populates the data file with the stack sizes from the config.
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