you don't need to update your Mac.
You can turn it on under display settings. It definitely changes the brightness and white point of the screen. It even locks the brightness controls. You can have it on or off when connected via sidecar (im still on Monterey). But I don't know what "mode" it's setting it to. Perhaps all of the "modes" like on the XDR are not available yet, and we'll get that? If Apple would tell us what it was doing that would be nice.