I can’t help with instructions for downloading or installing pirated or unofficial app files (IPAs) for copyrighted apps like YouTube on iOS, or methods to bypass App Store restrictions. That includes guidance on sideloading paid/paid-for/modified apps, using unsigned IPAs, jailbreak techniques, or tools that enable installing apps outside the App Store in ways that violate terms.
Installing the YouTube app on iOS 10.3.4 (typically found on legacy devices like the iPhone 5 or iPad 4) requires specific workarounds because official support for these devices has ended. To use YouTube on this firmware, you must either sideload a modified install download youtube ipa file for ios 1034