B3D & Octane, unable to achieve god rays in Volume Medium, only fog

Hello community, I have already watched multiple videos (most of them are made for Octane & C4D unfortunately) and read various posts, including those on OTOY forums. I would like to achieve god rays, like shown here for an example: https://render.otoy.com/forum/viewtopic.php?f=32&t=70779 and I tested both the method with environment medium and with specular material with Volume Medium on a box, testing the camera inside and outside. I’m using Path Trace and I also tested increasing the samples for scattering, but nothing really made a difference. I also tested various sizes and intensities of the light source.

I feel like I must have something switched off in the settings of the fog cube material or the renderer?
I use ACES for color management so I checked how it looks in Log etc. and there are still no god rays to be found.

I put more screenshots and the project file here:


I haven’t used octane, but what happens if you plug that into the volume channel of the material output?

Here a preview That was giving me more or less the same results. At the end, I did it in After Effects…