I finally solved my problem. But I would like to know other solutions as well to get by this.
So I’m not going to mark this as solved because there are other ways when it comes to dynamic texturing and materials, so it’s open for debate, come in, don’t be shy 
I used
UMaterialInterface* LoadedMaterial = LoadObject(nullptr, TEXT(“/Game/container_Mat.container_Mat”), nullptr, LOAD_None, nullptr);
I loaded the material without the constructor helper and made a parameter.
Removed TextureB I don’t need it anymore, it now takes feed from TextureD
If you manage to upload/import an image from disk and don’t know how to do and get stuck like me , this thread will help and it helped me, credits to the solver of the thread.
How to apply a UTexture2D to a UStaticMeshComponent? - Development Discussion / C++ Programming - Unreal Engine Forums
So you also have to set the material inside the material options in the editor, and give it a parametric name.
Cheers