Id guess it goes against the terms of use and can get your ip banned.
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
Have you looked at "Tube Archivist" at all?
backup now or perish your data
I leverage a VPN and yt-dlp.
If helpful I can share the scripts I use to download new videos from channels. If you are seeking to download an entire channel... you need to consider the bandwidth that the VPS service will charge. I say use your home machine, a good VPN, and have at it.