As someone who has built event pipelines from GDELT data, I'd advise folks to not start (a GDELT project) with high expectations. Not only are there plenty of duplicates, but tagging quality is all over the place, especially for non-Western media.
Agreed, it's very hit or miss in some situations. I'm hoping to keep evolving this to clean it up and eek out more salient information.
I think GDELT is the best source, nothing else comes close to coverage in my opinion, it's just that all the articles it gathers revolve around world events, as opposed to all of the millions of topics of discussion and niche interests people post about.