Hi y’all, one more thing:
after connecting the cables correctly and double-checking 5x, I still couldn’t get my setup working – until I found this thread:
Initially I’ve had my cable hooked up to a USB-C power supply, but it wouldn’t charge, even though 5.0V definitively arrived at the purple wire of the EMLID no-plug-cable. After reading the thread above, I tried a 12V power supply, and now it works flawlessly.
So the 5V stated the data sheet (yes, 5-40V…) might work if the cable is only 0.1m long (?), or it means “floor-rounded 5V from actual 5.4V” 
So my suggestion to anyone struggling & reading this is simply go for a stronger power supply. Works for me. 