Almost all of the feedback is for light mode, all the apps I use are in light mode (except VS Code and iTerm) so my end-user feedback will be way more relevant in light mode, not so much in dark mode (I could only comment on the esthetic, not what other tools tough me to expect).
I sorted the feedback in each component by how impactful they felt.
I feel like the playground background color can get in the way in some demos, while it helps on others. So overall, I feel it would be better white, like in https://mantine.dev/core/input/. One example where it gets in the way: https://mui.com/joy-ui/react-button-group/#introduction; this leaves a weird taste:
On the slider though, I don't mind https://mui.com/joy-ui/react-slider/