It would be very helpful to view a PDF Print view of a form without having to publish and then create a form.
Thank you for your idea. We understand the desire for it and will consider it for a future release.
As a workaround, you can leave an already created form instance open in a different tab while you work on the design. See details around the 1 minute mark in this video: https://youtu.be/vFKG9V39Fww?t=56
The new PDF renderer is exactly aligned with the form layout preview, so this special print-preview is no longer necessary.