

Iirc, tested it out quite a few years ago, and I had to use a software that would both decompile and recompile the PDF, and while it was decompiled, I had to remove the repeating pattern I didn’t want with something like Notepad++. File got recompiled a bit over 50% bigger iirc, maybe different compression methods, but the pages themselves didn’t seem affected.
Sadly can’t remember the name of the program I used for compiling and recompiling, only that it’d do both and that I looked for how to remove watermarks from PDFs. Also the program was certainly offline.
Found a few candidate tools though can test neither now, mutool (part of the mupdf tools), PDFtk, qpdf, pdf2txt (name sounds familiar though it might be memory playing tricks).
If any of those could be found as a single portable exe around 2020, chances are it is the tool I used for it.