The official YouTube app for iOS does not currently offer a public beta program. While Google previously used TestFlight for early builds, that program has been "paused" for several years.
beta via TestFlight represents a unique opportunity to provide critical feedback and explore experimental features before they reach the general public. The Role of TestFlight in the Apple Ecosystem
Click the YouTube TestFlight invitation link on your iOS device.
To install the YouTube beta on your iOS device via TestFlight, you must first download the TestFlight app from the App Store and then access an official invite link.
You cannot contact YouTube support for help with beta bugs. The only recourse is the "Report a Bug" link inside TestFlight, which sends raw data to developers (who rarely reply).
Drainage Lancashire