Import this JSON file into ACF Pro.

posts-loop-block-field-group.json

[
    {
        "key": "group_633d6d5baf705",
        "title": "Posts Loop",
        "fields": [
            {
                "key": "field_633d6d636cac6",
                "label": "Selection Type",
                "name": "selection_type",
                "type": "select",
                "instructions": "",
                "required": 0,
                "conditional_logic": 0,
                "wrapper": {
                    "width": "",
                    "class": "",
                    "id": ""
                },
                "choices": {
                    "recent": "Recent posts",
                    "select": "Select posts"
                },
                "default_value": "recent",
                "allow_null": 0,
                "multiple": 0,
                "ui": 1,
                "ajax": 0,
                "return_format": "value",
                "placeholder": ""
            },
            {
                "key": "field_633d6dc86cac7",
                "label": "Category",
                "name": "category",
                "type": "taxonomy",
                "instructions": "",
                "required": 0,
                "conditional_logic": [
                    [
                        {
                            "field": "field_633d6d636cac6",
                            "operator": "==",
                            "value": "recent"
                        }
                    ]
                ],
                "wrapper": {
                    "width": "",
                    "class": "",
                    "id": ""
                },
                "taxonomy": "category",
                "field_type": "multi_select",
                "allow_null": 0,
                "add_term": 0,
                "save_terms": 0,
                "load_terms": 0,
                "return_format": "id",
                "multiple": 0
            },
            {
                "key": "field_633d6e076cac8",
                "label": "Limit",
                "name": "limit",
                "type": "number",
                "instructions": "",
                "required": 0,
                "conditional_logic": [
                    [
                        {
                            "field": "field_633d6d636cac6",
                            "operator": "==",
                            "value": "recent"
                        }
                    ]
                ],
                "wrapper": {
                    "width": "",
                    "class": "",
                    "id": ""
                },
                "default_value": 6,
                "placeholder": "",
                "prepend": "",
                "append": "",
                "min": "",
                "max": "",
                "step": ""
            },
            {
                "key": "field_633db31877d50",
                "label": "Select Posts",
                "name": "select_posts",
                "type": "relationship",
                "instructions": "",
                "required": 0,
                "conditional_logic": [
                    [
                        {
                            "field": "field_633d6d636cac6",
                            "operator": "==",
                            "value": "select"
                        }
                    ]
                ],
                "wrapper": {
                    "width": "",
                    "class": "",
                    "id": ""
                },
                "post_type": [
                    "post"
                ],
                "taxonomy": "",
                "filters": [
                    "search",
                    "taxonomy"
                ],
                "elements": "",
                "min": "",
                "max": "",
                "return_format": "id"
            }
        ],
        "location": [
            [
                {
                    "param": "block",
                    "operator": "==",
                    "value": "acf\/posts-loop"
                }
            ]
        ],
        "menu_order": 0,
        "position": "normal",
        "style": "default",
        "label_placement": "top",
        "instruction_placement": "label",
        "hide_on_screen": "",
        "active": true,
        "description": "",
        "show_in_rest": 0
    }
]