Python virtualenv on MacOS apparently not activated

Question

I have created and activated a python virtualenv on my MacOS.

I have also installed a list of modules as listed in my requirements.txt

A stripped down version of it is the following:

python-dotenv==1.0.1

this is also valided:

▶ pip freeze | grep -i dotenv
python-dotenv==1.0.1
(.venv) 

However when I am trying to run my program, part of which has the following code

from dotenv import find_dotenv, load_dotenv

I get:

ModuleNotFoundError: No module named 'dotenv'

What am I missing?