Even just an option to set the primary app theme color based on Material You would be nice, but the option to use surface colors from Material You would be nice as well.
Not asking for any changes to the design or layout (Android mode is perfect) just specifically the Material You colors
I would also love a sepia color theme. Having a tan/beige background with dark brown accent colors would be really nice to use. I love these colors on reader modes in web browsers.