The channels are usually with stolen credentials. i.e. when you see an Elon Musk stream on your home page, it's because a creator you Subscribe to had their channel taken over and the content replaced with fake Musk streams.
People really under-value the credentials for such things and I think it's part of the same problem as when streamers who aren't used to this life yet forget about privacy considerations and end up with a phone number or worse home address known to fans.
If you have a meaningful Youtube income, you need to spend some of your next Youtube check on say two Security Keys. If you like them, buy some more for everything else, but since Youtube is your income, step one lock Youtube with Security Keys.
Once that's required, errors of judgement possible through limited understanding or sleep deprivation cease to be a problem. Baby didn't sleep properly all week, some idiot screwed up your banking, and now Youtube keeps sending emails. You get another stupid Youtube email or at least you think so and either
1. You give Bad Guys your password and maybe OTP, so they steal the account and maybe in 5-10 days you and your fans can seize back control, meanwhile it's used to run scams
OR
2. Even sleep-deprived, confused and bewildered you will not post your physical Security Keys to Some Russian Guy's PO Box, Somewhere else, 12345. Your account remains in your hands because without that physical object they can't get in.