In AOSP you need to pass in a value to @HiltAndroidApp and @AndroidEntryPoint because there is no support for the plugin.

Gradle:

@AndroidEntryPoint
class MainActivity : AppCompatActivity()

@HiltAndroidApp
class FooApplication : Application()

AOSP:

@AndroidEntryPoint(AppCompatActivity::class)
class MainActivity : Hilt_MainActivity()

@HiltAndroidApp(Application::class)
class FooApplication : Hilt_FooApplication()

For more info see this guide: https://aayush.io/posts/snippet-hilt-in-aosp/