Once you've successfully installed YouTube on your Android 4.4.4 device, here are some tips and tricks to enhance your experience:
Since the Play Store blocks you, you must manually install the app using an APK (Android Package Kit) file. This is similar to installing a program via a .exe file on Windows.
Because the official app often crashes or fails to load content on such old software, many users prefer third-party "clients" that are more lightweight and still receive updates.