I have eventually received the PCBs, soldered everything and done a quick initial test. The sound was coming through but the effects were not really working great. I'm sure this is a software issue that I'll fix with more testing, hopefully.
In the meantime this is the Github repo I'm using to host the project:
github.com/ilcardella/pico-pedal
I also have 4 PCB which I won't use, I can post them if anybody is interested. Unfortunately they have 2 missing routes (my bad) which require soldering of 2 short wires. Easy workaround.