I personally use devices with wildly different displays. I use traditional LCD displays for my desktop, and I use a Daylight Computer with an e-paper display. I would like to be able to use light mode on the Daylight Computer, and a dark mode theme on my other devices. Right now, I have to decide on one, or manually switch all themes as I switch devices.
I would like an option to disable theme synchronization. When theme synchronization is disabled on a device, it should only use cookie data to persist the theme. Otherwise, it should use the theme saved to the account.