iOS has an option in their Settings --> Accessibility --> Hearing Aids settings called Live Listen that allows you to listen from the device's microphone in your hearing aids. Is there anything like this in Android?
What I'm trying to input, through the TRRS input, is audio from a communications 2-way radio to hear in my hearing aids' through the Bluetooth connection. I've tried Bluetooth adapters that claim to pair with hearing aids, but have not found any that do, in fact, pair with my hearing aids. My HA's pair easily with my Galaxy A51 phone.