No reaction of brand new EM9291, when using (even different) M.2 USB adapters (e.g. Waveshare USB TO M.2 B KEY)

Thank you for your help!

You (Sierra Wireless) want to sell radio modules B2B and give professional service via a forum,
and ask me to use a multimeter to find out which test point is connected to what signal?
Suggest reverse engineering your radio modules? Is this your serious suggestion?

Sierra Wireless has schematic of EM9291 to look for this information, at least some of your hardware colleagues.
If this information is not public, just tell it.
This question will come of up more than once in future, so I think even a technical note (or similar)
on “hardware bringup” would be helpful, especially when using signals, which no other
manufacturer seems to be using.

I found the same suggestion for the previous product EM9190:

It would be nice if you could clarify this!