TSQL -- Extract JSON values for unknown/dynamic key in sub-object (not an array)

I'm using DataTables, DataTables Editor, JavaScript, and MSSQL 2016.

I'd like to parse this string in SQL Server:

{
    "action":"edit",
    "data": { 
                "2019-08-03":{ 
                                "Description":"sdfsafasdfasdf",
                                "FirstFrozenStep":"333"
                             }
            }
}

I don't know how to access the key "2019-08-03". This represents the primary key, or the DT_RowId in DataTables Editor. It's dynamic... It could change.

Historically, I have just manipulated the data in JavaScript to a FLAT object, which is WAY easier to parse in SQL Server:

{
     "action":"edit",
     "DT_RowId":"2019-08-03",
     "Description":"sdfsafasdfasdf",
     "FirstFrozenStep":"333"
}

HOWEVER, I would like to know how to use json_query, json_value, and openjson() to drill down to the "dynamic" key mentioned above, and then access its values.

Here are all my FAILED attempts:

declare
    @jsonRequest nvarchar(max) = '{"action":"edit","data":{"2019-08-03":{"Description":"sdfsafasdfasdf","FirstFrozenStep":"333"}}}'
    ,@json2 nvarchar(max) = '{"2019-08-03":{"Description":"sdfsafasdfasdf","FirstFrozenStep":"333"}}'
    ,@jsonEASY nvarchar(max) = '{"action":"edit","DT_RowId":"2019-08-03","Description":"sdfsafasdfasdf","FirstFrozenStep":"333"}'


    select
        json_value(@jsonRequest, '$.action') as [action]
        --,json_value(@jsonRequest, '$.data.[0]') as [action]
        --,json_query(@jsonRequest, '$.data[0]')
        --,json_query(@jsonRequest, '$.data.[0]')
        --,json_query(@jsonRequest, '$.data[0].Description')
        --,json_query(@jsonRequest, '$.data.Description')
        --,json_query(@jsonRequest, '$.data.[0].Description')


select
    [Key]
    ,Value
    ,Type
    --,json_query(value, '$')
from
    openjson(@jsonRequest)



SELECT x.[Key], x.[Value]
FROM OPENJSON(@jsonRequest, '$') AS x;

select
    x.[Key]
    ,x.[Value]
    --,json_query(x.value, '$')
    --,(select * from openjson(x.value))
FROM OPENJSON(@jsonRequest, '$') AS x;

SELECT x.[Key], x.[Value]
FROM OPENJSON(@json2, '$') AS x;


    select
        json_value(@jsonEASY, '$.action') as [action]
        ,json_value(@jsonEASY, '$.DT_RowId') as [DT_RowId]
        ,json_value(@jsonEASY, '$.Description') as [Description]