they started changing all of this as you mentioned, but I think the tips already posted will work
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.
There's probably a simpler way to do this, but if you run the channel URL through yt-dlp (commandline video downloader) it'll make a .json file for the channel.
In the file it'll have sections titled "channel_url" and "uploader_url". The channel url will be the one formatted like youtube.com/channel/UC-----
% yt-dlp --print playlist:channel_url -I 0 https://www.youtube.com/@nasa
https://www.youtube.com/channel/UCLA_DiR1FfKNvjuUpBHmylQ