I use Razer products (I know, I'm insane), and I just turned on "THX Spatial Audio", and suddenly I can hear everything I'm suppose to. I could hear people get close, I could hear 5 different teams fighting all around me, and exactly which direction they were in. Yet again, I shouldn't have to use this feature, or other 3rd party applications, to even be able to play the game.
What's also kinda funny is that people think Respawn keeps adding wall hacking legends, because no one knows how to fix the audio. I suggest finding someone who does. Audio is C-R-U-C-I-A-L to Apex.
Edited: Testing different settings for THX, and I can hear the audio get better, and then the game just goes back to being bad. So, I'm assuming Apex doesn't like it when you try to actually hear the game.