I think you should think about why you bought this device. It mainly is a collection of a few peripherals in a very neat package:
- an I2S headphone amplifier-chip
- a few buttons
- a small square ST7789 display
It is not a ready to use gadget that only needs some software. In fact, the software that Pimoroni supplies should be seen as an example of what you can do with great hardware like this.
This software was written many years ago, and the software itself and the install-program is not really supported and maintained. I think this is ok for a hardware shop like Pimoroni is. So you are on your own to figure out what to do (and you already made some nice progress).
I would really suggest a different approach: look for example programs for the individual components:
- a simple program that plays music (I would recommend mpg123)
- a simple program that processes buttons
- a simple program that uses an ST7789 display to show something
If you have all that, you know what is needed and how to do install and program it. And then you can maybe understand what is going wrong with the installer or sample application.