For those using Google Drive, the Google Workspace Marketplace features various add-ons for PDF management.
This is a comprehensive freeware option that supports unlimited file sizes and numbers for merging without watermarks.
If you are looking for a reliable and safe way to manage PDF documents, here are legitimate free options and insights into why official versions are preferred over "cracked" software: Safe and Free PDF Tools
The official Icecream Apps website offers a free version that allows basic splitting and merging without the security risks of third-party cracks.