(Long read warning) been having this problem for a while now, it was manageable at first but got worse over time and then got to 1:1 volume with the game after I plugged in an aftermarket PowerA Fusion Pro3. The fix on the stock controller was to update it (which I did) but you can't update a PowerA controllers firmware without the pc app, which I did at college but no change
I've confirmed it by calling myself and I could hear the game almost fully clearly and I know it's not sound leak cause I'm able to blast music through them at college without an eye being batted
Every fix online is to update the Realtek drivers but I'm on Xbox
I'm gonna buy an external mic soon cause I think it might be band bleed, but is this actually a software/firmware issue?