Python 3.12.3: PySide6s ffmpeg multimedia backend fails to load on Windows 10

I'm on Windows 10 Pro, running Python 3.12.3 and have installed PySide6 in a virtual environment and tried to use a QMediaPlayer to play a mediafile, which fails with the following being written in the console:

No QtMultimedia backends found. Only QMediaDevices, QAudioDevice, QSoundEffect, QAudioSink, and QAudioSource are available.
Failed to initialize QMediaPlayer "Not available"
Failed to create QVideoSink "Not available"

After doing a lot of trial and error I discovered that the following makes the ffmpeg backend work correctly:

os.add_dll_directory(sysconfig.get_path('purelib') + '/PySide6/')

I would expect that PySide6 would do that for me...

I have attached a test python script.