I like how you are experimenting with the possibilities. That’s a good way to learn.

I didn’t look at all of the files, but here are a couple comments:

• If it were me, I wouldn’t use a separate manager for every widget. I would only use one for the whole screen. I also probably wouldn’t bother making TimerService or ParseService. These can just be methods on your screen manager class (unless you are using those same methods across multiple screens of an app). In my view, making so many managers and services over-complicates the app and makes it more difficult to understand.
• In TimerService you have a dependency on the timer and button notifiers. The service layer should know nothing about notifiers, which are part of the state management layer. You don’t need to register the notifiers in GetIt either. Just directly instantiate them in your state management class.