Quote - Images you're getting from cameras are designed to be seen on a computer, using the sRGB standard. Images coming out of your render should be designed to also be seen on a computer, using the sRGB standard. The sRGB standard is not a linear representation of luminance. In sRGB, it is incorrect to assume that doubling the value of a pixel should cause it to be twice as bright.

Ah, a clue. sRGB is a representation of luminance? just not 'linear'... which I take to mean: on a grid, the line would be straight from one point to the next. So, do I take it to understand this is what is meant by linear colour space? a means where doubling the value of a pixel does cause it to be twice as bright?

So, gamma is all about brightness, not colour. Well, I did say I was thick. Of course it's about luminance. The renders are dark. So, we're taking an image and converting it from some curved to straight luminance value. When I think "picture" I think colour, not luminance. Yet, this is what most people fail to understand: how important proper luminance management is.

Now, armed with this concept, let's look at the rest of your explanation.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks