Begin play is just for testing purposes.
The problem is that the reference viewer still indicates a hard reference, despite using a soft reference only in the game mode.
So despite using a soft reference, even if I never load it, it looks like the problem remains that the the entire reference chain of the soft referenced object is loaded into memory - it appears both in the reference viewer and size map.
I must be doing something wrong, except I’ve reviewed the video and documentation and I can’t see how I am doing anything different.