No module named ipykernel_launcher

I was facing the same issue some time ago. Un-installing and re-installing jupyter from your virtual environment using conda/pip may help.

Installing pip correctly is the answer

https://opensource.com/article/19/5/python-3-default-mac#what-to-do

install pip in the new directory, and from there- download jupyter-lab again.

I found uninstalling the version of Python then reinstalling it worked for me with no issues.

The error is due to the unavailability of the module named ipykernel_launcher. (reference)

Try this, this should work.

pip uninstall ipykernel # this may or may not be installed.
pip install ipykernel