For android you can create chunks from the project menu. It should be under Android if I am not mistaken.
If you want to package the video file outside of the OBB file, you can create a custom downloader that downloads the video file to the device’s external storage after the installation is complete. You can also use a web server to host the video file and download it to the device as needed. This will most likely require you to use another service outside of Unreal Engine. Streaming doesn’t have to reduce the quality depending on how you load and buffer the video.
The maximum size limits are: 150MB: Maximum compressed download size of APKs for one device generated from app bundles.
Meaning that you need to have a very small game in order for it to be uploaded on the Google Play Store. I suggest the method of streaming the video to the game. However, my knowledge of how to achieve this without any research is very low.