My (working) setup:
I use an Android phone (Nothing phone 2a) which is quite close to bare Android, I think.
With this, I can increase the volume above normal limits (for which I get a warning from the phone). With this volume level, I'm able to hear MRA and Spotify in a good level, although I'm using Earplugs.
The audio system is Cardo Packtalk Edge.
The iPhone / iOS does not allow this extended increase of the volume I think. Also separate adjustment of volumes per function is not possible on iOS.
Regards,
Murat