In that case, you’re safe to just delete the implementation of GetEditorIcon, and it will use the default widget icon. You only need to provide your own custom icon if you really want it to show up with a distinct icon in the editor.
If you were to inherit URichTextBlock, you’d get the rich text block icon without having to override anything. Maybe we could figure out why you couldn’t use that directly in the first place?
If you really want to create your own style set to make an editor icon, we can walk you through that, but it seems overkill for a single widget type.