Set layer smooth border
Setting a smooth border without enabling Edge creates a smooth effect around the content.
In
Screens / Aux.⚓
Select a layer.
In Properties, click Border to show the corresponding settings.
Keep the Edge toggle disabled.
Toggle Smooth to create a fading effect around the content.
In Edge / Smooth, set the H size, V size and Opacity.
If needed, toggle Round to apply round corners settings and set the round corner radius.