All that leads to behaviour specific error related to OS version (Voice HAT on Raspberry Pi). Problem with sudo not playing music was resolved after installing pure "Raspbian Stretch Lite" and adding all necessary drivers.
I may be able to contribute a bit. I have a 3B+ and use the built-in BT to connect to a Logitech Audio Adapter which feeds my stereo. On first attempts using VLC, audio was horrible, mostly silence with occasional blasts of sound - severe stuttering to say the least.
However, using either mpg123 (for mp3s) or aplay (with wav files), sound played fine, ...
It is unclear why you think you need sudo or what the commands you are trying to run actually do, BUT the issue is almost certainly related to your PATH.
Invoking su does not preserve the environment (see man su) so you loose access to some files accessible to pi.
The way you installed the programs can also affect access.
You can preserve your environment ...
To answer my own Question at least to a small extend:
VLC seems to offer a something similar to pygame but with the advantage that (to my knowledge) no screen is needed and it plays pretty much every data Format.
Here a quick link: https://linuxconfig.org/how-to-play-audio-with-vlc-in-python
As for the code, Iam still greatful for every advice, especially ...