Guys, I'm having trouble with a large file. I have tons of PDF files, and need to combine / merge them into 1 file.

BUT, I need to repeat several of the individual pages in-between, alternating. Hundreds.

Problem 1) The online program / site I usually use can't handle the file size and it just basically bootloops.

Problem 2) Alternative sites are TOO CLUNKY to be able to easily insert and rearrage this many files at once (*copy / pasting that one repeated file)

I hope this makes sense. Tips?