@bennuttall have you looked at https://pypi.org/project/pypdfium2/ ?
It's the bindings to Chrome's PDF engine
@bennuttall man pdfseparate
pdfseparate extract single pages from a Portable Document Format (PDF).
@bennuttall I usually use cpdf for stuff like this, see https://github.com/coherentgraphics/cpdf-binaries. Command line tool, so also nice for scripting for which I use it a lot.
Documentation here: https://www.coherentpdf.com/cpdfmanual.pdf