Google no longer supports KitKat. The latest version of the standard YouTube app requires Android 8.0 or higher. You cannot install the official YouTube app from the Play Store on a KitKat device anymore.
The short answer is:
: This is widely considered the gold standard for old Android versions. It is an open-source client that uses the NewPipe extractor to pull videos without needing Google Play Services. youtube lite apk android 4.4 4