Raspotify killer
Run any of the examples while you have raspotify service running, and it kills all audio for the raspotify service. Restarting the service does nothing, and only a system reboot brings back the audio. This is tied to the backlight function.
I just ran into the same issue. Did you trace down the exact issue? Were you able to find a way to use the screen and play audio at the same time?
EDIT: Looks like it's been discussed here: #9
Fixed it by setting backlight=13 in the constructor for the ST7789.
Added notes for this in the examples, thank you - https://github.com/pimoroni/st7789-python/commit/9aabd781810abda2f6165c34150753f9e26d867f