The standard YouTube app from the Play Store likely won't work on Android 4.4.2. Instead, you need a version compatible with (the technical name for KitKat). Last Supported Version
You must enable "Unknown Sources" in your security settings to install these files manually. Youtube Apk Download Android 4.4 2
NewPipe Legacy: NewPipe is a popular open-source YouTube client. They maintain a "Legacy" version specifically for older Android versions like 4.1 through 4.4. It is ad-free and very fast. Is it Safe to Use Old Versions? The standard YouTube app from the Play Store