So yeah you are all smiles huh!
A custom mesh shader now needs to pass an instance culling struct TRDGUniformBufferRef into the Uniform Buffer for a RGD pass.
The FPrimitiveUniformShaderParameters for the FPrimitiveSceneShaderData array now has a build() method which is way more easy to understand and same with the FInstanceSceneShaderData, yei!
They renamed the SHADER_PARAMETERs to use FVector2f, FVector4f, FVector3f, etc etc instead of using the old FVector2D, FVector4, etc, what a pain to change all in my plugins.
So yeah thanks Epic to make me refactor the core of everything I have done the last year
It all works now, but man I aged 1 year by fixing all