Why does my baked lighting look so flat?

This is already baked with production quality, but it feels as if it’s basically on or off, so ambiance at all… anyone know why?

Is it the HDRIBackdrop plug-in which breaks things or?

Oof… yeah ok it seems it is the HDRIBackdrop plug-in.

ON

OFF

That thing doesn’t work out of the box with neither raytracing nor backed lighting it seems.

I’m guessing Epic just developed it as a proof of concept for a demo and then abandoned it?

Ok, this is an indoor part of the level, so maybe HDRIBackdrop isn’t entirely to blame?

The sliver of light is from an opening, and the room should be lit by a weak spotlight, but it still looks extremely flat.

Anyone have any pointers?

Bit off topic but this explains very well tone mapping:

Esp trade offs and why they do happen.