An example ACF block.json which disables align controls, but forces a default to wide

block.json

{
    "name": "automatic-wide-width",
    "title": "Automatically Align Wide",
    "description": "A demo block.json for a forced align-wide block",
    "apiVersion": 2,
    "acf": {
        "mode": "edit",
        "renderTemplate": "render.php"
    },
    "supports": {
        "align": false,
    },
    "attributes": {
        "align": {
            "type": "string",
            "default": "wide"
        }
    }
}