If I understand correctly, you want the output as a full-page raster image wrapped in a PDF rather than a regular vector-based PDF? A vector-based PDF is much more efficient to open, render, it’s smaller, faster to open, faster to download, prints to better quality, allows text to be extracted…
To my knowledge, this is the first time this has ever been requested. You would mind sharing your use case?
It is possible to get what you want, but in two passes.
Output the template to a raster image (PNG, JPEG, TIFF…). This can be done either directly by the Create Output stepor, if you have Workflow and Image, by using the Digital Imaging task to ratserize the PDF.
Use a second template that takes the rasterized images from step 1 and prints them as page backgrounds, with the template being otherwise empty (i.e. dynamic images on blank pages).