Garage band no audio input sound. Tried numerous audio interfaces and built in mic etc...(and yes...monitor is on)

Ive got myself an imac 2014 running big sur and I've installed garage band after several years away from Macs. I've tried 2 audio interfaces now and both have had the same issue. I assumed the 1st one had a problem so i returned it and bought a different one. Both were plug and play no drivers required. Behringer um2 and the M-audio M-track solo. Both have solid reviews for Macs.

I've tried numerous ways to set them up and I never get any audio input from Mics or Guitars. Im not a noob as i've used Logic in the past on an older Power PC mac so i totally get how to do this stuff. Or so i thought. I've since come to the conclusion that theres something else going and but i do not know what. I've now tried the built in Mic and that too with monitoring on and all the audio set up correctly. (ive been at this for a week)

I've reset the pram, ive reinstalled garageband 3 times, ive reinstalled Big sur once. I cannot work this out. I've made aggregate devices, multiple configurations...Everything. Not once have i managed to get any input sound from any devices. The clincher for me is the built in mic works in photo booth so i know it's good but not a single flicker when trying to get it working in garageband.

Please help....This iMac was test run to buying the new iMac in a nice orange colour and now im having second thoughts.