Instead of building from scratch, fork (open source) or YouTube Vanced Legacy (discontinued) and rebrand for stability.
If the browser is too slow, you might look into "Legacy" or "Lite" versions of video players, though many third-party apps also rely on updated Google Play Services, which are no longer supported on Lollipop. youtube android 5 version
If you are using a legacy device, the last major version series confirmed to support Android 5.0+ (API 21) was , released in late 2021. Last Stable Version Minimum OS Android 5.0 (API 21) Availability Can be found on archival sites like APKMirror Alternative Solutions Instead of building from scratch, fork (open source)
This version will not auto-update. If you install it, you must disable auto-updates in the Play Store, or it will try to update to a version that crashes instantly. Last Stable Version Minimum OS Android 5