After activate new environment, Python will not start

On Windows 11, miniconda3, version conda 23.3.1, received the following error by simply trying to start Python.

(base) C:\Users\username>activate gmat2022

(gmat2022) C:\Users\username>python --version
Python 3.9.0

(gmat2022) C:\Users\username>idle
Fatal Python error: init_import_site: Failed to import the site module
Python runtime state: initialized
Traceback (most recent call last):
  File "C:\Users\username\AppData\Local\miniconda3\lib\", line 73, in <module>
    import os
  File "C:\Users\username\AppData\Local\miniconda3\lib\", line 29, in <module>
    from _collections_abc import _check_methods
  File "C:\Users\username\AppData\Local\miniconda3\lib\", line 416, in <module>
    class _CallableGenericAlias(GenericAlias):
TypeError: type 'types.GenericAlias' is not an acceptable base type

For one thing, why isn’t the file path under miniconda3\envs?

The HKEY_CURRENT_USER Registry setting for Python is C:\Users\username\AppData\Local\miniconda3.