From what I've read Fuschia is not at all self-contained. The UI is fully driven by and targeted towards Google the search and ecosystem.

But those write-ups were years ago and there hasn't been new reviews with much UI focus since then.

Operating Systems are not a very well defined subject. Linux doesn't include a UI layer for instance and that isn't considered a problem. Being tied to a particular experience limits the potential applications of the OS, so in many ways I would consider the lack of opinionated experience a good thing.

There is now a UI experience available as part of Fuchsia in the workstation product, but I wouldn't overly index on it as it's just one take on what you could use Fuchsia to build.

You’re probably right, though for an OS that’s the kind of dependency people would prefer to have removed anyway.