Just going to sound really pedantic here, but RGB does not capture the entire colour space. In fact, it only captures about 35% of the colours the human eye can perceive.
https://www.oceanopticsbook.info/view/photometry-and-visibil...
Okay, but that was a really useful metaphor if incomplete in a lot of ways. It made me say “oh”.
This is solved through https://en.wikipedia.org/wiki/Primary_color#Imaginary_primar... that sit outside the visible spectrum.
You seem to be conflating "RGB" with one particular RGB color space: sRGB. That's a common enough conflation to make, but not appropriate when you're trying to be pedantic.