Have you looked at sys.path?
(i.e. poetry run python -c "import sys; print (sys.path)")
A very quick&dirty solution could be appending the sys.path with wherever poetry installed the packages (probably a venv depending on how you configured your poetry according to this: https://python-poetry.org/docs/cli/#install).

If you see tensorflow installed in the project specifc venv (e.g. in <PROJECT-DIR>/.venv/Lib/site-packages/) my best bet is that something is fishy with your project installation or poetry installation.