Is there some special or secret way to get a "new document" in Preview on Mac?
This is exactly what a document template on macOS is intended to do. You make one document then flag it. Next time you open it (from automation, script, recents, finder) it creates a new empty document with precisely the setup you want.


https://support.apple.com/guide/mac-help/create-document-templates-on-mac-mchlp1341/mac


Even though Apple documents this clearly and plainly, I suspect most people find it a “secret trick” or hidden gem once they have an itch like yours that needs scratching.