I have a new HP all-in-one printer I can use to scan to PDF. Unfortunately I haven't found any Debian app that can produce multiplle-page PDF scans. The only app I have any scanning success with is XSane (its docs are not good, nor is its
user interface).
The PDF Tool kit (pdftk) can be used if you're smart enough to decipher the man page, but I created a Raku module that does the trick of combining PDFs
with a much friendlier CLI (thanks to my New Zealand Raku and Debian
friend David Warring and his wonderful PDF modules).
Best regards,