It seems to me that the tooltips in the Recolor Artwork panel are backwards.
The left button's tooltip tells me that that button controls Saturation and Hue, but once selected, the slider's tooltip tells me that it adjusts Brightness, which it actually does.
The right button's tooltip tells me that that button controls Brightness and Hue, but once selected, the slider's tooltip tells me that it adjusts Saturation, which it actually does.
If I am misunderstanding something, then the tooltips are at the very least extremely confusing.
I'm using Illustrator 25.2.1 on macOS 10.14.6.