

A few nitpicks
Subpixels would not be perfectly monochromatic unless they were laser displays. Quantum dot can get kinda close though.
if mixing light additively didn’t create new colors then mixing paints subtractively wouldn’t either. the results of those processes still result in light that can activate our cones with combinations of wavelengths in the exact same way.
I think the semantics of what color light is doesn’t matter which wavelengths are used to produce it, but what it looks like. We don’t say something is yellow because it has wavelengths of light that look yellow on their own, we say something is yellow because it looks yellow. Likewise people use the term white light all the time when there’s no single wavelength that produces white.


You also started thinking about it, you started trying, and with some practice you’ll learn how to stop when you need to. It’s not about stopping, it’s about… a bunch of complex stuff because nothing in our brains has a simple straightforward explanation as much as we like to pretend it does.