Return all values from objects using OPENJSON()

Here is my problem: My JSON may vary based on API response and there is no guarantee that "shortTitle", for example, can be present in my JSON next time when there is a post request. I have to figure how to "loop" (if that's the correct term) through JSON to get all fieldID and contents without losing any data.

Here is the query:

DECLARE
// hardcoded json to simulate a post request
@json nvarchar(max) = '{
    "itemTypeID": 13,
    "authorRights": {
        "fieldID": 15,
        "content": "abcd"
    },
    "language": {
        "fieldID": 7,
        "content": "abcd"
    },
    "url": {
        "fieldID": 13,
        "content": "abcd"
    },
    "shortTitle": {
        "fieldID": 8,
        "content": "abcd"
    },
    "data": {
        "fieldID": 6,
        "content": "2022-03-02"
    },
    "summary": {
        "fieldID": 2,
        "content": "abcd"
    },
    "subject": {
        "fieldID": 60,
        "content": "abcd"
    }
}';

BEGIN

SELECT* FROM OPENJSON(@json)
WITH(
fieldID bigint '$.data.fieldID',
content nvarchar(255) '$.data.content'
)

END;

This query returns fieldID and content only for "data" (results). How can I return fieldID and content for all objects?