Earlier quoted context omitted.
I'm assuming Iced has no A11 support (these projects never do). Probably no RTL support. Possibly no reusable "system" widgets like open/save dialogs.
Can you clarify what you mean by "these projects never do"? Your comment comes across as dismissive. Especially since I already noted that it was lacking a11y in my original comment. Anyway although a11y and i18n support have not been implemented, they are planned. https://github.com/iced-rs/iced/issues/250
If Iced actually gets cross-platform accessibility support, that's great! Very few projects have that today. More certainly wouldn't hurt. But until it does, you shouldn't base a DE on it.
Edit: The issue you linked to is about RTL support. That's also required, but doesn't touch on a11y.