Back in the depthai directory, make sure the requirements are installed for it (
python3 install_requirements.py) and then run:
python3 depthai_demo.py -s disparity_color
Here is running it on my OAK-D:
So on the opencv-contrib-python, sometimes the issue could be the install location, and which Python you are using.
I suspect a system Python is being used instead of a user Python, and
opencv-contrib-python was installed along the Python that is not being used.
Which OS are you using?