Just to add another AuthZ approach to your great comment:

ReBAC for Fine Grained Authorization (FGA) is also something that's becoming more common at the moment. Google released their Zanzibar whitepaper explaining how they implement FGA for things like YouTube and Drive and it's lead to a lot of new tooling based upon it.

I'm working on a project at the moment with quite complex document management with various levels of access. Auth0 open sourced their FGA implementation recently as OpenFGA which looks ideal for our use case. As it's all fairly new there isn't much info out there about different ways of implementing it so we're kind of figuring it out as we go.