If you are using the latest Onward - Reduce Tech Addiction app, version 2.6.2, you can make changes to your Onward Smart Filter settings:
> Tap the gear icon in the upper left of the app
> Tap Smart Filter
> Tap your mode to make changes
If the current settings aren't enough, shoot us a note detailing exactly what sites you would like blocked or unblocked we'll try and make the changes on your behalf.