As an added point of reference, Turing released in late 2018 and RDNA2 released in late 2020.

I Googled a little to see if the GTX 1660/Ti supported Vulkan Video and found this page from Nvidia[1] that says Pascal or later, so I wonder what the blocker is in this program.

1: https://developer.nvidia.com/vulkan/video/get-started