Carplay no sound- HELP

I recently purchased a 2015 bmw 428i and i’ve been having carplay issues. At first i thought it was the weak battery that came with the car so i replaced it with a new one and the sound works but only for a bit. I didnt install the apple carplay so im not sure if its an internal issue or some wiring is wrong, i’ll start the car up, the sound will be working fine before it glitches out or completely stops. The music is still playing, since the timestamp is moving, but no sound is coming through. The weird thing is that it isnt just the music thats not coming through, its all of the sound from my car period. No sensor beeps or any sounds coming from the speakers, so im not sure if this is an issue with my vehicle or whoever installed the apple carplay.
I’ve tried resetting the radio, i’ve disconnected and reconnected my phone, tried bluetooth too and nothing fixes it permanently. This sucks since the car works perfectly fine other than that so if anyone has any advice i would appreciate it.

Side note: the apple carplay was intended for an M5 i believe, not sure if that affects anything