Need help with audio interface and Discord

Hi, new mac user here. Im struggling to use my audio interface on Discord for calls, it picks every sound of my system, i cant separate the inputs for mac, i just need the 1-2 of my interface to do the work, but the 3/4 input (as virtual) is the loopback, how can i work this out? cant even watch a youtube video while im on a call, i haven't test this on another apps like Zoom or Google Meet.