Even with sRGB as default and a well-calibrated display, the choice of gamut transformation determines the hue that you get on your display in comparison with the monochromatic light. It's really not clear cut.

That all depends on the color space and transformation you use for your gamut mapping.

This is not how it works. Most monochromatic colors fall way outside the color gamut of a typical display, and are therefore impossible to show accurately.

For example, see this image: https://upload.wikimedia.org/wikipedia/commons/thumb/9/91/SRGB_chromaticity_CIE1931.svg/440px-SRGB_chromaticity_CIE1931.svg.png Your phone can probably show you all colors within the triangle. But monochromatic light traces the outline of the weird shape.