Keep in mind “great engineer” will be a subjective term that means different things to everyone.
To Meta, it might mean cream of the crop, $1m+ engineer. To early Google, it might mean Stanford grad with deep CS knowledge. To a no-name startup, it might mean someone who accepts the job who takes initiative and knows how to crank out ugly code quickly on AWS and makes good prioritization decisions.
What's the last "deep CS" thing that Google built? Isn't most of what comes out of their shop re-wrapped known tech with mediocre UX?