how to make your own feedback and apply it to all slides as a feedback master .
The Feedback for question templates does have its own Feedback Master. Go to the VIEW tab > Feedback Master. There you'll see a set of layouts for Correct, Incorrect, Try Again.
Simply adjust the look and feel, positioning and size of objects, fonts, or whatever else you want to change. Keep in mind this is a Master so it will affect every question slide in your course globally.
Working with Feedback Layers: https://community.articulate.com/articles/working-with-feedback-layers-in-articulate-storyline-2
Quick video overview: