Have a look at how labellers work in ATProto. It forms a good foundation imo, perhaps sufficient as they currently stand. Good prior art if we abstract beyond just atproto, not sure what W3C might have already in the works that is similar enough.

https://bsky.social/about/blog/03-12-2024-stackable-moderati...

https://roost.tools is another group you may look into. They are broader in scope for Trust & Safety across the internet at large. Their current focus is a couple of OSS tools for builders, but the ambition is big and something to appreciate.