Keep Volume via Bluetooth helmet at MAX?

I set my motorcycle helmet volume to MAX, iPhone to MAX, Maps volume to MAX, yet I can just barely hear directions through my earplugs on the highway, and then Siri seems to unilaterally decide to turn down the volume without notice and I miss critical information.

Phonecalls come through loud and clear though, so I know the phone and speakers are capable of delivering the necessary power.

Is there any way to set Maps volume to remain at 130dB via my Bluetooth helmet? It’s a SENA if that makes any difference.

I just figured out how to turn off decibel warnings, and set the Bluetooth type to “hearing aid,” instead of headphones, so maybe it will quit thinking that it’s damaging my ears.

Can anyone think of any other settings I need to change to disable ALL “automatic volume modifications”, and ensure that ALL volume remains at MAX through my helmet?

THANKS!