Hi, I’ve been able to generate shader debug info in UE5.1 using :
r.Shaders.Optimize=0
r.Shaders.Symbols=1
r.Shaders.SkipCompression=1
In renderdoc I can see the HLSL source, but shader debugging is disabled, when hovering the debug button, renderdoc displays “Debugging DXIL is not supported”.
Any workaround ? switching to vulkan maybe ?
This may not be fully accurate, but here is what I have heard:
Renderdoc currently does not support debugging DirectX Intermediate Language (DXIL) shaders. To debug HLSL shaders in Renderdoc, you will need to use a different rendering API such as DirectX 11 or OpenGL.
Switching to the Vulkan API may allow you to debug your HLSL shaders in Renderdoc, but this will depend on Renderdoc’s support for the Vulkan API and any compatibility issues with Unreal Engine 5.1. It may be worth checking the Renderdoc documentation and forums for more information on using the Vulkan API and debugging shaders in Renderdoc.
Hopefully this can point you in the right direction! 
Thanks !