Hmm AFAIK a well chosen password made of random stuff, not some word from a dictionary, is pretty much uncrackable for both PDF & ZIP. it need social engineering skills to deduce & persuade, rather than CPU power.
There are tools that will take a pdf or zip file & run an entire dictionary of all words of a given length, but brute force vs random gibberish of arbitrary length is different -
but ithe latter is also impossible to memorise, & once you create passwords file as an aide memoire, well there goes your security
