Stoneblock
To create a Stoneblock-like modpack, you can simply set the surface settings as shown in the configuration below.
config/skyblockbuilder/common-config.json5
{  
  "World": {
    "surface": true,
    "surfaceSettings": "minecraft:bedrock,254*minecraft:stone,minecraft:bedrock"
  }
}
The downloaded file also sets the default world type to Skyblock, generating Bedrock at the top and bottom of the
dimension. There is only one spawn point, and a starting inventory is included, as shown below:
config/skyblockbuilder/starter_item.json
{
  "items": [
    {
      "item": "minecraft:wooden_pickaxe",
      "nbt": {
        "Unbreakable": true,
        "Enchantments": [
          {
            "lvl": 2,
            "id": "minecraft:efficiency"
          }
        ],
        "display": {
          "Name": "{\"text\":\"Infinite Pickaxe\"}"
        }
      }
    }
  ]
}