Getting JSON of a web part

[metkhoo]

Introduction
The documentation page https://pnp.github.io/pnpcore/using-the-sdk/pages-webparts.html ( "Using the SDK > Pages > Working with web parts and text parts" ) states that when adding a CONFIGURED web part we should use the Workbench.
In the case where I want the JSON for a configured Image web part that contains text overlay and image shape, I find that the Workbench does NOT support the extra (new) options of text overlay and image shape. It only supports the "properties".

The documentation does not suggest any other way to get this JSON.

Question:
How can I get the JSON for an image web part that contains text overlay and image shape options?