This User playing World War Z has the exact same problem as you do with his game: I cant active Vulkan Api . This User is able to play other games using Vulkan but not WWZ.
Download GPU-Z and make sure that your GPU card shows "enabled" by having Vulkan and OpenCL boxes check marked.
If they are check marked then the problem isn't the AMD Driver but that specific game.
NOTE: as Kingfish posted, Please post your Computer setup including current Windows version, etc and if it is a laptop, EXACT MAKE & MODEL.