I'm now the maintainer of pypdf and PyPDF2. I merged everything back into pypdf. pypdf is the way to go. PyPDF2 will be deprecated.
Original answer:
PyPDF2 is mainained again since April 2022. We made massive improvements in text extraction and added type annotations. The docs were improved, the interface is now more pythonic.
Internally, we deprecated Python 3.5 and lower + added a lot of unit tests. This simplifies the development / maintenance.
PyPDF2 is free and open source.
PyPDF2 is a pure-python library without any dependencies.