The parent controls need significant improvement. 
1.  Link the app to phone Face ID or password feature.    That is needed because right now a kid can grab your phone and make any change in the app. 
2.  Add a "reward" feature to give a child more time or extend a bedtime?  Such a pain now to make a change and then remember to change it back.  
3.  Setup multiple use/no-use times.  Only bed time exists, but may need more control for other times in the day.  

4.  Add non-time restricted domain or categories.   I want my son to always be able to communicate via text/FaceTime even if during bedtime or after he has used his time.