I second what others have said. Unfortunately, with the demise of oakmoss, true, deep chypres have disappeared and one has to look into vintage. I recommend smelling a chypre 1.0, so to speak, and the best is indeed Chypre, which can still be found sometimes for not unreasonable prices (in the still good 80s reformulation). That will unclog your memory. When I was a kid, I wasn't consciously paying attention to my mom's perfumes, but when I smelled Chypre, I immediately recognized it.
But the chypre base is like a backbone, the impression of the perfume can vary a lot: from the classic, relaxed citrus chypres, to the sharper green chypres to the butch leather chypres - all have a different feel. The common component is a certain abstract elegance,Turin once used the analogy of a houndstooth tailleur.
New chypres don't smell like old chypres to me. They may try to reproduce some of the feel (abstract elegance), but not the actual smell. Still, it doesn't mean that they don't smell good on their own terms. rue cambon, enlevement au serail, private collection jasmine white moss etc etc