How do we define era? It's a slippery term. But I will note that the current crop of top CBs (and this has been the case for 5-6 years now, IMO, so it's relevant in terms of thinking of Van Dijk "in his era") is the weakest it's been in a long while - an opinion of mine which I do not think is nostalgia-driven. The push towards the all-action dominant #6 has pulled top prospects away from playing CB and towards playing CDM, such that many guys who would've been in the mixer for "best CB in the world" ten years ago were instead developed into midfielders. All you have to do is look at FIFPRO World XIs from the last few years to see the drop in top defensive quality.
It helps him that he's maintained a very high level into his mid-30s, as the fact that he was a very late bloomer as a top player would otherwise be problematic (he shares this with Thiago Silva, although even Silva broke out about three years younger than VVD). But his late blooming makes it hard to assess him with regards to era. He's a 1991, which puts him in a weird spot between the really good mid-to-late 1980s CBs (spanning roughly from Thiago Silva to Hummels and Boateng, encompassing also Ramos, Pique, Godin, Chiellini, etc.) to the really good mid-1990s CBs (Varane and Marquinhos being the standard-bearers here). Who is his era? By the time Van Dijk broke out, Varane had been a top CB for 5 years despite being 2 years younger, but has now retired while Van Dijk is still at a top level. Van Dijk's late development curve means that he straddles "eras" pretty awkwardly.
With regards to his all-time PL status, he's in the mixer for #2 no doubt (Terry is fully, unambiguously, no shred of debate #1).
And with regards to BDO, all that need be said is that Modric and Rodri have two while Xavi and Iniesta have none, and that the only Italian centreback with one was at absolute best the third best centreback of his country's generation.