Yes but ESRB is for computer games only, too corporate and I’d hardly call it independent. I also don’t like the actual rating system. Their one pro is that they have some authority, but even that is only for North America.
What my ideal would be is just an externally verified list of content warnings, that are not ultimately reduced to a single character. Next to each item would be either “light”, “medium” or “heavy” modifiers. Separate into categories mandated by law like 18+ vs not 18+, but leave the actual rating to adults.
I don’t think you can have enough rating boards.