Is there a way to copy a widget that I have fully configured in one Slate app to another one? I would like to avoid having to recreate everything.
You can use your usual copy and paste commands on widgets. Just select them in the Canvas pane on the left in your Slate app, press Command + C, navigate to your second Slate app, press Command + V and the widget will appear. Alternatively, you can also click on the three dots right next to your widgets name and select copy/cut to copy/cut the widget, but you will have to use Command/STRG + V to paste.
You will also get popups, indicating whether the copying and pasting was successful.