Drawing of Fragment is lagging my loading animation

Question

I am using AnimationDrawable to show loading. Something like this:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/loader_00000" android:duration="12" />
    <item android:drawable="@drawable/loader_00001" android:duration="12" />
    <item android:drawable="@drawable/loader_00002" android:duration="12" />
    ...
</animation-list>

I am using Fragment. I have this animation in ImageView as src and I am showing it above the content of fragment_layout.

I am running animation like this:

(image_view.drawable as AnimationDrawable).start()

Animation works quite well. But I am loading stuff from a server and populating it to components below animation. I am loading stuff in a background thread. Using CoroutineScope with Dispatchers.IO. However, populating of stuff is causing lagging of my animation. How can I improve it to not lag? Is it possible? Is there a better approach?