Okay, final update for now → it also works with Bulk Add Queue Items and I just need some tea 
I forgot to flip the delimiter for my CSV file in the activity here:
With that, it properly added the queue item:
prashant1603765
V_Roboto_V
ashokkarale
arivu96
sharazkm32
Anil_G
pikorpa
postwick
jaswanthvarma.gottumukkal
adi.mehare