YouTube has this problem to an insane degree, some large businesses are run from a single person's long standing Google account and there's no way to give another YouTube account any privileges you might want an employee to have without giving them access to your entire Google account and all attached services including your emails, the ability to locate and wipe your phone, all the photos on your phone via Google photos, your calendar for it's entire history, I could go on.

It's completely insane, and the closest they've gotten to adding anything like this is letting people have comment moderators on live streams, not videos where people have wanted comment moderators from day one, just live streams.