The exact opposite, but close enough.

> to also define which RGB values have a corresponding Pantone. Ie. “You can accurately print this number!

This is still backwards. Pantone has not gone through the RGB numbers and figured what inks they could make. Pantone has made inks, and when people need to work on a screen, with projects that will use those inks, they need mappings that will give them a reasonable enough approximation of the colors of those inks to do their jobs. What is printed will not match what is on the screen (irt color.)

> Give the printing apparatus these numbers and they’ll mix the pigments precisely based on formulas they have (and probably also paid for?)

Absolutely. But those numbers will have nothing to do with either RGB or CMYK, other than that approximations of those colors in RGB were used to do the design. Prepress people and designers are composing with RGB, but printing with Pantone. It's as if you composed an orchestra piece on a piano.