I found this post to be extremely useful.
Basically, it contains instructions to set up PyEnv in a way that we have one Jupyter notebook that works with multiple Python interpreters.
One caveat: make sure your ~/.bashrc or ~/.zshrc does not contain any lines that mess with $PYTHONPATH. I haven’t been able to get this setup working if I have something like the following in my ~/.zshrc:
PYTHONPATH=/Users/prem/whatever/:$PYTHONPATH
I think it interferes with the way pyenv finds the location of site-packages.