Update: Looked through the forums more and found that Alex6679 and others have done some amazing work on this and it should get merged in the future. This seems to have solved my problems. Github Link
Thank you all.
Using Teensy 4.0 with Audio Shield as an audio interface Line in and Line out through USB audio to an iPad mini with USB C.
Apps like AUM, Koala Sampler, and Voice Memos have issues with pops in the incoming audio. Issue starts after about 2...