D3D11 is the by far most used 3D API on Windows (there are thousands of D3D11 games versus hundreds of D3D12 and much fewer Vulkan games), and most games don't

D3D11 is the by far most used 3D API on Windows (there are thousands of D3D11 games versus hundreds of D3D12 and much fewer Vulkan games), and most games don't actually have better performance with D3D12 or Vulkan anyway. So from a pragmatic 'bang for the buck' point of view, D3D11 both for the frontend and backend makes the most sense.