Actually, what happens is a channel you were subscribed to, or one which you have consumed enough content from to influence the YT algorithm.... has been compromised, taken over, the password was discovered by crypto miners.

They take over the channel, change a bunch of settings, etc... then start spewing out the usual Space-X live stream crypto-mining pyramid-scam. Sometimes if you look at the channel hosting the live-stream, you can sometimes still see clues to the old channel you were subscribed. You have to audit through the videos and playlists, old comments, etc...