I see the same error on bullseye - the patch should be a bit different, as the source evolved. The line to be replaced in /usr/lib/python3/dist-packages/virtualenv/seed/embed/via_app_data/via_app_data.py with the same as in the patch here fix is
if name_to_whl['setuptools'].path.is_relative_to(BUNDLE_FOLDER):
_get('pkg_resources', Version.bundle)
(somewhere close to lines 120-126 - if you like I can produce a correct diff)
Best,
Dima Pasechnik
