Why does import of preinstalled libraries cause import error, but symbols undefined otherwise?

[mikew67]

Warning - Old computing guy, but new to CircuitPython, VS Code, and this extension:
So running CircuitPython 9.0.0-alpha 6 on Raspberry Pi Zero 2 W and attempting to use this extension in VS Code (latest) as an IDE. But "import" behavior appears to be broken for pre-installed libraries.
For example, with a simple Blinky example:
import digitalio
throws an error on Run without Debugging
ModuleNotFoundError: No module named 'digitalio'
OK, "Fix this" suggests removing unneeded libraries (It's preinstalled in the CP image) But now any reference to digitalio throws an "undefined symbol" error

If you run the code outside of VS Code and your extension (e.g. with the mu editor and serial port), it runs fine. The "import digitaiol" goes by silently.

What's up. Pilot error? Would love to use your extension for its many features.

BTW: "Choose Circuit Python Board" is properly set to RPi Zero 2 W, but the VS "language" could only be set to generic "Python", not "CircuitPython"