Happens for some devices:
* Huawei P30 Android 10 - build number 11.0.0.174
* HUAWEI P30 Pro Android 10 - EMUI 11.0.0.
* Huawei Nova 5T

Not reproducible on:
Huawei P20 Pro Android 10 - build number 10.0.0.197
Sony Xperia Z5 Compact (4.6 inches) Android 10
Galaxy Note8 Android 9.0.0
Galaxy S8 Android 9.0.0

CAMERAX VERSION: 1.1.0-beta02 (and all alphas)

DESCRIPTION:
It previews and records with a very low framerate when using:
VideoCapture and Preview UseCases + target aspect ratio of 16:9 + CameraSelector.LENS_FACING_BACK

P.S. It works fine when instead of aspect ratio, target resolution is set (added that as a comment in example code)

CODE TO REPRODUCE:

--- LAYOUT:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android">
<androidx.camera.view.PreviewView
android:id="@+id/preview_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</FrameLayout>

--- ACTIVITY:
private lateinit var cameraProviderFuture : ListenableFuture<ProcessCameraProvider>

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// ......

val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
cameraProviderFuture.addListener(Runnable {
val cameraProvider = cameraProviderFuture.get()
bindPreview(cameraProvider)
}, ContextCompat.getMainExecutor(this))
}

private fun bindPreview(cameraProvider : ProcessCameraProvider) {
val cameraSelector: CameraSelector = CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build()

// Case: Preview
val preview: Preview = Preview.Builder()
.setTargetAspectRatio(RATIO_16_9)
// Works fine when using actual size (with:1080 height:2097):
//.setTargetResolution(Size(binding.previewView.measuredWidth, binding.previewView.measuredHeight))
.build()

// Case: Video
val recorder = Recorder.Builder().build()
val videoCapture = VideoCapture.withOutput(recorder)

// CaseGroup
val useCaseGroup = UseCaseGroup.Builder()
.addUseCase(preview)
.addUseCase(videoCapture)
.build()

preview.setSurfaceProvider(binding.previewView.surfaceProvider)
cameraProvider.bindToLifecycle(this, cameraSelector, useCaseGroup)
}