If all you need is to split the files, then any print-to-PDF driver will do. Win 10 has it built-in. For Win 7 and before, CutePDF works well but the installer was weaponized to drop adware and finding a clean older version is getting harder by the day. Possible alternatives with virtual printers: Foxit Reader, Nitro PDF reader.
Beyond splitting files, only Adobe Acrobat is able to deal with the mess. Unless the house is on fire, the only sane method is to fix the source and regenerate the PDF files as desired. (The reason for that is that PDF files do not have internal structure. The contents are just a bunch of objects at particular positions on the page. It is up to you to repair e.g. word wrap if a change pushes a line beyond the margin.)
Beyond splitting files, only Adobe Acrobat is able to deal with the mess. Unless the house is on fire, the only sane method is to fix the source and regenerate the PDF files as desired. (The reason for that is that PDF files do not have internal structure. The contents are just a bunch of objects at particular positions on the page. It is up to you to repair e.g. word wrap if a change pushes a line beyond the margin.)