You may be thinking of the official insider fan guide, Outer Banks: Pogue Life . This book is styled as a scrapbook and includes "deep" lore like secret pages from Big John's journal and insights into local legends. Status of the Series
The confusion regarding "Season 10" and "deep paper" likely stems from the series' episode structure or specific guide materials: Outer Banks - Season 10
While the main series is ending, the creators have expressed interest in developing potential spin-offs in the future. You may be thinking of the official insider