It's a dupe, but the closed question isn't actually too broad. In the case that a question is asked with clear effort/quality that is a dupe of a question seriously lacking in effort/quality, closing as a dupe the other direction (i.e. closing the older question as a dupe of the new one) is the preferable course of action.
In the case the older, much worse, question is closed, probably the thing to do is make a meta post or flag a moderator if it's really clear cut. We can't make a dupe of an already closed question (viz. we can't have an already-closed question also be a duplicate of a new question, because posts can only have one close reason), so if we really want to have things closed in the ideal manner in that circumstance we might have to open the old question and then dupe it, or just delete it so there's no duplication. In the meantime the new question should be closed for whatever reason it needs closing (e.g. too broad in this case) so it's easier to see the real reason why it's closed instead of having to follow links.
Once the close reasons are dealt with, if it's still a dupe of the other question we can figure out what to do with it on meta.
Note that the existence closeworthy/uncloseworthy dupes of uncloseworthy/closeworthy (respectively) questions will always be a contentious issue when it crops up. That's because being a dupe means that two questions are the same in terms of substance (i.e. the things that matter in terms of answering it), so their receiving differing treatment is/would be indicative of our community doing something it disagrees with, like treating questions/people differently based on how they talk or what background they come from in a question, or whether certain users asked or answered it. That's not to say these situations don't come up, just that when they do and you go to post on meta about it you should be aware that the question about how to handle the duping will necessarily entail a discussion of why one of them ended up closed while the other didn't and if that's okay and what we think about it.