RPI: Error on first start (Python importlib.metadata)

I;m running a Raspberry Pi 4 with 11/bullseye.
First I installed the outdated mopidy version from debian sources. I removed it (with purge) and installed current version acc to instructions. When i run mopidy I get this error:

Traceback (most recent call last):
  File "/usr/local/lib/python3.11/importlib/metadata/__init__.py", line 563, in from_name
    return next(cls.discover(name=name))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/mopidy", line 33, in <module>
    sys.exit(load_entry_point('Mopidy==3.4.2', 'console_scripts', 'mopidy')())
  File "/usr/bin/mopidy", line 22, in importlib_load_entry_point
    for entry_point in distribution(dist_name).entry_points
  File "/usr/local/lib/python3.11/importlib/metadata/__init__.py", line 981, in distribution
    return Distribution.from_name(distribution_name)
  File "/usr/local/lib/python3.11/importlib/metadata/__init__.py", line 565, in from_name
    raise PackageNotFoundError(name)
importlib.metadata.PackageNotFoundError: No package metadata was found for Mopidy

Can anyone guide me what I did wrong?
Thanks a lot!

Bullseye has Python 3.9. Upgrading system python is not easy and normally ends badly. It’s rarely a good idea. I suggest you run latest Debian rather than try and bodge it with an old version.

I upgraded due to Home Assistant requirements (installed in venv). Nowadays I think Docker would be the better choice for HA but I did not spend time to restore a clean system…