How to fit correctly any figure from figma to app mobile (android) with any screen resolution?

I have created a simple figure with Figma, a blue rectangle and a red rectangle with rounded corners, and displayed them in a mobile application. The big problem is that in my mobile application, the blue rectangle takes up the entire screen and the red rectangle is not vertically centered and doesn’t fill the width of the screen. So there is a big difference between the Figma result and my mobile application result.

Here is the link to my Figma file:

See below the screenshot of my mobile phone.

I use Android Studio with Android Compose and the plugin Relay for Figma.

If someone can help me solve my problem and explain how to fit any figures from Figma correctly to any smartphone screen resolution, it would be greatly appreciated.

Help me !!!