According to an updated press kit shared by GSC Game World, STALKER 2: Heart of Chornobyl will arrive in Q1 2024.
GSC Game World has not made any kind of official announcement regarding the postponement, so it's best to take this information as a rumour.
"STALKER 2: Heart of Chornobyl launches for PC and Xbox Series S|X in Q1 2024. The game will be available on Game Pass on day one, and pre-orders are open on our website, as well as on Steam and GOG. Pre-orders for physical editions are available on the official website,"
GSC Game World has not made any kind of official announcement regarding the postponement, so it's best to take this information as a rumour.