Will the game have Vulkan/ray tracing support on upcoming AMD GPUs(RDNA 2/Navi X2/Big Navi) maybe after launch with a patch?, or will it be DX12/NVIDIA exclusive for ray tracing?

I think AMD GPU will support ray tracing, because xbox series x and ps5 have AMD APU and cyberpunk will have ray tracing on consoles. Maybe not right away, maybe after some time

I'm aware of that, but on PC they're probably using NVIDIA's GameWorks and their GPU's RT cores which are proprietary thus AMD doesn't support it, so they will need to manually add support via AMD's GPUOpen to utilize RDNA2's ray tracing cores, unless they have exclusivity agreement with NVIDIA for ray tracing support on PC.

I'm so disgusted with Jen-Hsun's refusal to support open standards. He can try to sell as much ray tracing hardware as possible, and more power to him, but he should be helping to establish open industry standards for APIs and software so that innovation can occur unbounded.