While the current version of YouTube requires Android 8.0 or higher, Uptodown maintains a repository of older APKs that were built for Jelly Bean devices.
android compileSdkVersion 33 // latest still supporting API 16 defaultConfig applicationId "com.example.youtubelegacy" minSdkVersion 16 targetSdkVersion 33 youtube for android 4.1 2 uptodown
A: Disable HD playback in the settings (Settings > General > Limit mobile data usage > 480p). Also, close other background apps. While the current version of YouTube requires Android 8