The user cannot find a "YouTube iOS 12.5.7 APK" because it does not exist. However, they get YouTube on their device.
iOS’s walled garden means:
Apple allows users to download the last compatible version of an app if they have previously downloaded it. youtube ios 12.5 7 download apk old version
The YouTube app must already be linked to your Apple ID . Step-by-Step: Open the App Store on your iOS 12.5.7 device. The user cannot find a "YouTube iOS 12
Sign in with your Apple ID on a newer device (iOS 14+) and "get" the YouTube app there first. Once it's in your account history, it will appear in the "Purchased" tab of your old device. Apple Support Communityhttps://discussions.apple.com YouTube for iOS 12.5.7 Download - Apple Support Community The YouTube app must already be linked to your Apple ID
For users on iOS 12.5.7, there is only one safe, legal, and functional method to get YouTube working without "jailbreaking" the device.