YouTube Vanced was a successful modded version of YouTube that provided functionalities such as ad-blocking, background play, and SponsorBlock. It has been discontinued, though, and you cannot download it from official channels anymore. For alternatives, you may try ReVanced, which is an open-source project offering similar functionalities. To install ReVanced, download the ReVanced Manager from its official GitHub link, install MicroG (if necessary for login), and patch the official YouTube app. Downloading from third-party sources should be done with care to prevent malware. It is always best to check sources and refer to the official ReVanced documentation for a safe installation.