Copy Vulkan SDK from the vulkan installer volume to a directory in your hard-drive.
Install the SDK from your hard-drive and not from the installer volume by running $ sudo ./install_vulkan.py.
Add the vulkan env vars to your .bash_profile file with the root location set to the sdk directory on your drive. For example, if Vulkan sdk 1.2.154 is installed then the env vars should be set like this:
$ sudo ./install_vulkan.py
.For more info see: https://vulkan.lunarg.com/doc/sdk/latest/mac/getting_started.html