I think you definitely should improve the user interface of your app. It just looks too simple. No images, no cards, and no color. I would recommend you to start from this app (open source, you can take some reference from it).
I see you randomly generated a number of steps as the goal of the day. Not everyone can walk 4K steps. You will also need to get some more information from the user like Google Fit, such as their age, their weight, and also specific needs for certain users.
You have six screens, but only a few components or blocks on each screen. What I recommend you to do is to combine some screens into one single screen with the help of virtual screens. That way you can use memory efficiently.
What are all the elements you want to include to "Stay Healthy"
Gather validated reference material (and link back to it) for each element to provide to the user with information about the element, why and how it will help them to Stay Healthy, and what is the medical provenance behind your information.
Ensure you provide warnings to users about each element (when to not do it / when to stop etc.)
Plan your UI - start page, setup/registration/user details, activities/elements, logs and history of activities/elements, progress reports - targets etc.
Build and test workflow for each element
Combine all workflows into the UI
Test, test, test (get others to test too - they will find all the bugs you have introduced)
Then start looking at how to make it pretty
Then ask the community for suggestions and improvements.....
The most important aspect of such an app is user safety/health, you need to provide a lot of information and safeguards (and/or include legally sound disclaimers).
See here for an example of what I mean (NHS BMI Calculator) - the actual calculator is quick and simple, but the amount of information provided is immense!