Hello. I had this problem on my new Macbook air but this was solved with the help of a savvy apple tech.
I am in the same position now with my new iMac desktop. Audacity does not recognize my plugged in microphone and also my headphones. It only recognizes the internal input and output.
I tried explaining to the apple tech that the secret is going into security in system preferences but the tech said that usually a program like audacity would “ask” for permissions so there was nothing to adjust.
can anyone give me insight into what to tell the apple tech or how to solve the problem? Thank you.