You can edit any effect currently being used by an AnimTextBlock widget by looking for the effects data created by the plugin in the user project.
Example: default install path where the plugin copies the default behaviour effects
Since Effects are stored inside Data Assets, which are “data containers” that are independent from any level or widget, you can reference them from your own Blueprints/C++ code and modify their values at any time, without needing to have an Animated Text Block widget in your level to access them.
Edit Mode Preview
You can preview the result of your effects in real time in the editor. Editing the text will trigger an immediate re-shape and show any present effects. If enabled, typewriting will also automatically start.
Finally, there's a "Preview Effects" section in the widget's details with additional controls (such as previewing the text disappearance).