Adafruit Circuit Playground Express fails to upload
The actual error part of that stack trace is:

Port name - /dev/ttyACM1; Method name - openPort(); Exception type - Port busy.


You have something else using /dev/ttyACM1.  If you don't yourself have something open, such as a serial terminal or the Arduino serial monitor, then the most likely culpret is modemmanager.


https://majenko.co.uk/blog/diagnosing-arduino-problems-linux