YouTube has among the worst linkrot. Stuff gets deleted , hidden, or channels deleted for even the tiniest of supposed violations or reasons.

Same for downloading content. Over 15+ years, there have been so many tools that purport to download YouTube videos and they either don't work or get patched or full of bugs or malware. It's surprisingly hard to do, especially at any scale. more of an art than science. understandably, YouTube does not want people just downloading their content easily without paying for premium.