[Mailman-Users] Re: manage.py not found in virtual environment

seems to me, you are right:

(venv) mailman@arda:~$ mailman-web help
[...]
[hyperkitty]
    hyperkitty_import
    hyperkitty_warm_up_cache
    mailman_sync
    update_index_one_list
[...]

I followed the instructions: using pip to get mailman and deps basis is a debian bullseye with python 3.9 I just added one version constraint, because Mark told me to when I hit a bug during installation: mistune==2.0.0rc1

Yes, my settings live in /etc/mailman3