There had been suspicions around Rami Malek's Safin from pretty much the moment we was announced and the trailers did nothing to dispel those rumours. In fact, they seem to lean on the hints.
For instance, we knew that No Time To Die was being filmed in Jamaica some time before we got the confirmation that it was part of the plot. Set leaks had confirmed as much, but then we were told that when No Time To Die starts, Bond is retired (hence there being another 00 agent active again) and has chosen the island to put down his roots.
Jamaica should have pricked up lots of ears at that point, because it was infamously the setting for Dr No. In that story, Bond heads to the Caribbean on the trail of a missing British agent and follows it to Dr No's own personal island - Crab Key - off the coast.
Could it be a coincidence? Absolutely. But you don't drop that big a similarity and expect fans NOT to pick it up. And the story links don't end there...