I always disable it. Having everything using the same exact colour palette is boring/homogenized. The themed icons are even worse, simultaneously killing iconography art and making it much more difficult to differentiate between apps in the app drawer quickly.
Just the colour choices I don’t care for . There’s this kinds weird thing they do where background elements desaturated pastel , but then accent colours still pastel but super saturated that just lꝏks ugly to me
Previously on my non monet supported device , had to either (download app that let’s me set apps as greyscale|put up with bleh colours) . Ofc that has drawbacks where if app somewhat image heavy , am forced to keep it in coloured mode