Tonal Spot, Vibrant, Expressive, Spritz will each come with a preset of colours again based on the hues found in your wallpaper. The latter three options offer a wider range of accent colours with some not even part of the background image's palette.
Spritz, for example, uses more muted monochromatic tones that fit nicely with dark mode while Expressive offers more popping colours that still match the core ones from your background image.
The new features are still in the early development phase and with at least another several months ahead of the first Android 13 developer betas we might see other changes take place.
