For me nothing has helped still troubleshooting and since early access not being able to play. But what I have done is the following Maybe there is something that will help you out.
So I already did the following
-contacted Larian, first make a case so it is known to them
-verified the gamefiles.
-reinstalled the game.
-verified my audio settings making sure it was alright, only running realtek.
-try using the onboard soundcard
-runned it throught the launcher in Vulkan and DX11
-changed output from 44.1 to 48 kHz and vice versa within the Windows audio settings
-spacial audio off
-audio enhancement off
-disconnected game controller, it could be seen as a audio device by Windows, I read this somewhere on another sound issue post.
-reinstalled a clean version of the realtek drivers
-reinstalled gpu drivers through DDU
-disconnect the wifi attenna just to be sure, if you have one
-dissabled the mic just to be sure.
-used a DAC
-Used process Lasso and make sure all cpu cores are used at BG3
-Tried launching bg3.exe and bg3_dx11.exe as admin
-bios update
-bluetooth headset
-did a cmd sfc scannow, search for cmd run as admin and type: sfc scannow or DISM /Online /Cleanup-Image /ScanHealth
-did a cmd DISM HealthCheck, search for cmd run as admin and type DISM /Online /Cleanup-Image /CheckHealth
-did a cmd DISM RestoreHealth, search for cmd run as admin and type DISM /Online /Cleanup-Image /RestoreHealth
-delete realtek and used Windows audio driver
-Completely reinstalled Windows and this all over again
Hope this helps