Much less elegant workaround: carry earbuds or headphones to the live show to monitor the audio. Earbuds are hard to hear in a live music setting, and more bulk and kit to lose and fuss with—especially with iPhone 7 and newer needing an adapter for headphones.
https://www.amazon.com/Shure-MV88-Digital-Condenser-Microphone/dp/B010W6W8OW

