Well… Hm, it seems you have a complicated way of looking at the Cubase mixer. Stop it.
Open up your Cubase mixer, tell it to send your single input to however many channels you want. You can select channel one on your input device and have it sent to as many channels as you want. Did you know this? It’s just a routing process within the mixer.
So, from there, you can load each channel for whatever process you want - all channels receiving channel 1’s input and running simultaneously - and drop or raise your faders as needed to create your mix.