The jetpack might be awkward as the voice will not only echo in the jetpack but also come from behind you.
I used to have the voice synth app setup and amp in my side pouches but I realized people thought it was weird having my sound come from the hip, and they couldn’t understand me.
I’ve now moved it to my front thigh pockets and it’s much better. If there is a way to have the sound move forward toward people you are speaking with, while keeping everything concealed, I could see it working.