Audio stops when ios app goes to lock screen

Hello, I’ve made an app using Unity 2022.3.26f1 and the latest fMod, I’m struggling to get it to continue to play audio in the background on an iphone when the screen is off or the phone is locked.
I understand how to do this via Signing&Capabilities, and using the correct Audio Session via AppDelegate, but can’t get it to work. It will play when the app loses focus (i.e. on home screen) but when phone locks it stops.

Is this something to do with using fMod as the audio engine instead of Unity’s?