Android App Developer to Improve App Content Loading Issue

Hi There,
Happy new year to all the PPHers.

I have a native Android app that is written in Java.
It used to load in less than 2-3 seconds earlier but the previous developer made some changes for the new UI and following issues were introduced that is impacting user experience:
1. App loading time has increased to 7-10 seconds. It needs to be brought back to 2-3 seconds.
2. After 20 records on the timeline screen, the next set of 20 records shows loader and it takes time to load the content and refresh the screen. Previously it used to be free flowing, therefore needs to be smooth content loading because API call is less than a second.
3. The scrolling of the screen feels heavy and lags in loading next batch of content. This screen needs to be made free flowing content screen.

We checked the API response is 700 milliseconds but the way the UI is displaying the data is taking a lot of time.

I need an Android developer who can fix above issues without impacting any other functionality of the app.

Please also note following:
1. The app needs to be tested properly before passing it on to me for final UAT.
2. Not a single existing functionality should break as thousands of users use the app at the moment.
3. Coding standards needs to be followed.
4. Once you commit towards a deadline, please stick to it because the money for this job is to deliver on time.
5. This fix shouldn't introduce any other new issue.
6. If you don't understand anything or have any questions, immediately ask me instead of making assumptions.
7. Knows how to use BitBucket.
8. App works fine on Android 8 and above versions.

Please only apply if you can meet these and can deliver on time.