I am using the notes functionality in iOS as well as MacOS. My notes sync through iCloud. Works super.
Now, I'd like to have the notes displayed in my MacOS dashboard. Is there a notes dashboard widget that connects to iCloud ?
With the caveat that this is just one example of a notes widget, I've used Junecloud's Notefile app a bit, and it seems to fit your requirements of a widget that connects to iCloud. I can sync to iCloud or the app provider's JuneCloud sync. However, Notefile is not a free app (currently $4.99), so you'll need to look elsewhere if you want a freeware solution.
Junecloud also provides an iOS application for mobile devices (iPad/iPhone/iPod Touch) for $2.99 at the time of this answer.