pyside6 module not found

[ForeverNoob]

Hello,

I was writing a couple of programs under manjaro KDE. Now I've switched to ubuntu 23.04 and, when trying to run them, receive the following error:

ModuleNotFoundError: No module named 'PySide6'

Both programs have active venv. I also have a third program which used to work under manjaro but having the same problem now. Tried to create a virtual environment for it, but pip refuses to install pyside6 to it, claiming:

This environment is externally managed

Tried using pipx, which didn't help.

Any advise?

TIA