Android 4.4 KitKat was released in 2013. While it was a legendary operating system that powered millions of devices (from the Nexus 5 to budget phones), it has long been end-of-life (EOL). This means Google no longer provides security updates or official app support for it.
For those facing compatibility issues, downloading the YouTube APK (Android Package File) can be a viable solution. The APK is the installation file for Android apps, which can be downloaded from various sources. Youtube Android 4.4 4 Download Apk
Because of this, you cannot use the "Latest Version." You need the last build specifically compiled for API 19. YouTube on Android 4