Why does my audio goes to speaker everytime i connect to a voice channel (discord, ingane chat mic turned on) or calls)

So i have the iphone 13 pro max and have been using it as my daily phone and also for games. I connect it to my arctis nova pros wireless’ game dac whenever i game for better quality audio and also to be able use the headset mic for fps games. The Adapter used is the Apple-made lightning to charge and usb 3 and camera (connecting 5o the game dac audio input usb c port.)

my annoying issue is:

-whenever i am in any type of call, all audio goes to soeaker not in my headphones. When that happens, i usually check the audio outputs on control centre only to find my audio is on “iphone” or sometimes it goes “ speaker” while my headphones is not on the list. When i end the call or turn off mic on my game or disconnect from discord, my headphones are back on the list with speaker icon on it.

(I have went through the settings abd pls don5 offer me the call audio routing bla bla cuz i did all 3 choices and none helped. Even customer service and a dude from senior tech that calls you for assistance couldnt help.

so im trying my chances here for a fix.

blutooth is a 10000 no. And if ever thats the only fix, help me find a way the audio doesnt go crap when i turn on microphone .