how to enable Hardware raytracing on FEngineShowFlags

I have a custom viewport client that inherits from FEditorViewportClient, I am trying to enable lumen using hardware raytracing, it seems that function is not exposed, I tried everything on the EngineShowFlags variable, but not success.

Here is all I am calling:

No matter what I do the reflections are still screen space, instead of using the hardware features, all works in the normal editor’s viewport when I enabled it, but not for my custom viewport

Any clue?

Further investigation led me to this function:

Inside the LumenReflection.cpp, it seems the hardware reflections are not supported into standalone, I tested all those statements, they all are true, nevertheless lumen hardware reflection does not work, for now I am setting my post process volume to use hardware raytracing, the deprecated option, that is the closed I can get to have my viewport to the unreal’s main viewport visuals.

Cheers