What API should I choose when impl a real time ray tracer?

I want to write a real-time interactive GPU lightmapper for my renderer, like https://www.gdcvault.com/play/1024801/.

I found that there are many related tutorials here. Some use DirectX 12(Unreal is using it), others use Vulkan or OpenCL(Unity is using it), etc.

I know Direct X 12 works for Windows only. and Vulkan for all platforms, and OpenCL for various GPUs.

If I want to implement my idea on Windows 10 with NVIDIA RTX cards, which API should I use? What advantages will it have? For example, can all three APIs utilize hardware RT core?