I will say that for those who deal with a large number of scanned documents, PDF Harvester from CoolUtils on the website https://www.coolutils.com/PDFCombine will be a real godsend, which is much easier to use. Not only does it merge files, but it also automatically removes those annoying blank pages. Saved me a lot of time and will definitely do the same for you. You can start by using the free version on the website.