Change default file icons (for all files of that type)

I just set up a new machine running Big Sur 11.1 from scratch. I was reinstalling my go-to apps, but I noticed that the icons didn't change, even after I selected an app as the default for all files of that type.

For example, .wav files, by default, have album art (or are blank if there is no embedded art). On my old computer, the icon for .wav all changed to the icon of my default .wav player, which was VLC (the orange traffic cone icon). I'd like this to still be the case on my new computer, and I know how to change file icons one-by-one, but for the life of me can't figure out how to get all .wav files to use the VLC icon.

As pictured below, you can see that I manually changed a couple of the .wav files, but the rest remain unchanged, even after a reboot. Any help would be greatly appreciated.