Look for the final builds of YouTube Go from 2021-2022.
: Support for Android 5 officially ended around October 2021 . Attempts to use older versions often result in "Error 400" or prompts that an update is required when none is available for the hardware. Methods for Viewing YouTube on Android 5 youtube android 5 version full
Google Play Protect may flag the sideloaded app. This is a false positive. Tap “Install anyway” or ignore the warning. Look for the final builds of YouTube Go from 2021-2022
As of recent updates, Google has officially discontinued support for the YouTube app on Android 5.0 Lollipop. youtube android 5 version full