Picard is set in the original Prime timeline
As Kurtzman told GamesRadar: "[Picard is] in the Prime timeline, we're not in the Kelvin timeline. But the thing that was interesting about that movie is it was the one element of the film that's still in the Prime timeline, because it was the supernova, the destruction of Romulus, and Spock's jump [back in time] that created Kelvin."
While the events of Hobus are still there (the 2009 Star Trek depicted them), we never see any mention of Spock, the red matter system, or his traveling back in time. In other words, Picard seems to cherry-pick the events of Star Trek: Countdown, the direct tie-in into the Kelvin timeline. We know this because B4 is non-functional in Picard, while B4 winds up as Captain of the Enterprise-E in Countdown.