Ah, I see @kersing was on that thread & Pi based gateways aren’t my thing so I’d have not absorbed the details.
You asked about a concentrator for a Pi, did you see this bit - I’ve put in bold the words I think are most relevant:
It’s almost impossible to describe what skills are needed or for people to figure out if they have what they understand as being described, so it’s hard to say if you have the resources and we just need to help you find the right config, or if you should go with something with more direct support. If I have to do a Pi based gateway I use a RAK module with their installer.
As pin 22 would be the mPCIe connector, it’s likely that the ‘cape’ pin 7 referencing GPIO is most likely to the right one. But as it’s a second hand board, it could be that it is broken or damaged.