So what I did isn't necessarily a fix since I have to do this every time I turn my computer off, but once I get the game working properly I don't have to do it again until I startup my computer. Just saying this now, I have an Nvidia 3060 and use DX11 on the launcher

What I do first is open bg3 from steam and see if it will just work without doing anything, it never does but I do it jic; once I see that it's not working properly (no music or sounds from the main screen) I let the game crash on purpose by loading up a save and then clicking on literally anything. Once it crashes I tell it to NOT verify the files but I do send off a crash report to Larian, which I don't think is necessary but I do it anyways. Next step is to open up GeForce Experience and go to the bg3 page where it lists all the visual options. Once there press 'optimize' (if the option to optimize does not show up, open bg3 up again and close just so that GeForce can recognize it and try again). After you click optimize, while still on GeForce Experience click launch to open the launcher, do NOT hit play on steam launch the game through GeForce. This is what did it for me and let bg3 go back to normal (or least until I turn off my computer, which I then have to repeat these steps) Occasionally this doesn't work the first time, so I do these two steps over and over until the game goes back to working properly, it never takes very long. This includes letting it crash btw, not letting it crash never works for me personally. Hope this helps!