glitchpop okay, let's see where the issue is.
Can you please first try a simple patch which sends an audio signal to the outputs. E.g.
[dac~ 1 2 3 4 5 6 7 8]
That will help determine if your outputs are working or not.
The issue with the digital pin is likely due to the numbering scheme we use with the multichannel expander. In Pure Data the extra audio channels end up shifting the digital channel numbering up by 6. See here for a thorough explanation: https://learn.bela.io/products/multichannel/bela-mini-multichannel-expander/#pure-data
If you use the pin diagram in the IDE then the pin numbering for the digitals will be correct, for cpp and Pure Data. Failing that please send over your patch so we can have a closer look.