Going a little off-topic, but I believe that even though there are many note taking apps, every app is unique in its own way and features.
Some app is pretty straight forward and some may have many features loaded in them.
It greatly depends on users. Some may use Material notes and others Evernote.
All these apps including Google Keep etc have one core and common feature that is note taking. The only difference is method of engaging users.
Beside this when you are new to app development, one of the app to get you started is a note taking app. And I believe that every app is worth thousand dollars for its developer even though it’s a very basic app.
So the thing is instead of telling not to make apps because they are already made, let the developer build the app and who knows the developer might come up with some awesome features!!
And for your query @jackandrichardjunior
Just keeping in mind the idea of what kind of app you need, try to gather the components present in the builder and try to arrange and code them as per your need.
I am sure if no one had this idea you presented here, no one would have tried it and neither will except you. So the best would be try it yourself and I hope that you come with a great app