Modeling Help - RequestBody / Additional Properties (Freeform Key)

Hey Community! Does anyone know how to model the below in Stoplight? We have a JSON:API that takes a nested request body for a few of the end-points. The user can specify properties to write to the node or resource in our system.

I’m trying to render something like this:

Example Request Body:

"data": {
    "type": "people",
    "id": "1234",
    "attributes": {
       "user_can_specify_this": [{"value": "Some String Value"}]