Scientists -> ok, but would prefer to omit that

Discovered -> "Observe" is better

Gigantic Structure -> "Cosmic structure" is better than the subjective "gigantic", as everything cosmic is by definition gigantic and it seems to imply some sort of amazement at its size

in a

Hidden Zone of Space -> "Obscured" zone of space would again be better

So how about "First Observation of Cosmic Structure in Obscured Zone of Space"

I'm not an editor, and if I can come up with a more accurate and less sensationalized title, one can only conclude that whichever editor was behind this specific headline was deliberate in their choice of its clickbaity feel

Not sure “observed” is accurate, since we can’t see it from here. Discovered seems better.

And it is one of the largest we’ve seen, and it’s very close, so there is some amazement.

that implication is, I believe, the commonly understood one.

What, "aliens" or otherwise "artificial"? Is that the 'commonly understood' implication you mean? It's okay to say it. My question is, is it “commonly understood” or is it merely a convenient and very fun implication to assume?

I suppose artificial is the commonly understood implication when one uses the term structure, but if it is found in a hidden zone of space it also somewhat implies aliens.

"Should" not, yes - though it is here, it seems to me.