To get a Vanced-like experience on KitKat, you must use legacy versions of the software that are no longer officially supported.

Installing YouTube Vanced on Android 4.4.2 (KitKat) requires using older, "legacy" versions of the app, as current versions require Android 8.0 or higher

You must be cautious. You are downloading a discontinued modded APK from a third-party website.

(Lightweight, open-source)

YouTube for android 4.4 and below? PLEASE : r/androidafterlife

Due to Google's server-side changes, even the last compatible version fails to play videos or sign in. Switch to NewPipe or use a modern browser with ad-blocking for a functional, ad-free YouTube experience on KitKat.