When prompted that the current version is incompatible, select to install the "last compatible version" for iOS 12.5.7. Method 2: Safari Web App (The Easiest Alternative)
Please note that installing an older version of YouTube might expose you to security vulnerabilities, as you won't receive updates or patches. install youtube ios 1257 best
This works only if you previously had YouTube installed under your Apple ID. When prompted that the current version is incompatible,