Aborted virtualenv, broken reference for python3

Question

I ran the command virtualenv venv and aborted it halfway, and now, whenever I open a new terminal (Mac OS Catalina 10.15.2), I see the message:

dyld: Library not loaded: @executable_path/../.Python
  Referenced from: /Users/don/anaconda3/bin/python
  Reason: image not found

The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.

(Even though I uninstalled zsh quite awhile ago; not sure how it's still here).

I can't be sure exactly how this new behaviour occurred, though. Aborting the virtualenv venv call was just the last thing I did, not necessarily the cause of the issue.

Issues

• When I try to initialize Jupyterlab (i.e. using $ jupyter lab) I get the same error; the same thing happens for jupyter notebook (however, note the new line Abort trap 6):

dyld: Library not loaded: @executable_path/../.Python
  Referenced from: /Users/don/anaconda3/bin/python
  Reason: image not found
Abort trap: 6

• Notably, the (base) environment (provided by conda) that initializes by default whenever I open a new terminal is no longer there. See conda docs, section "Managing Environments".

There's a similar problem here, but the root causes don't appear to be similar (I wasn't downloading anything new...I think).