how do i insert embedded sheets from google docs?

Question

You need to insert the sheet table as an inline image

An InlineObject contains an EmbeddedObject such as an image.

Now, when you publish a Google Sheets, you have the option to publish it as pdf, but not image. This mean that you would need to perform an additional step of converting the pdf into a supported image format.
Alternatively you can obtain (and save on your Drive) the Sheet as a thumbNail by performing a Files: get request on the Sheet and setting fields to thumbnailLink. Mind that the thumbNail contians the whole sheet view – not only the data range.

Important:

When performing a documents.batchUpdate request InsertInlineImageRequest, you need to specify the uri in the format

https://docs.google.com/uc?export=view&id=PASTE_HERE_YOUR_ID