4K at half the framerate. Resolution scaling can change on a game-by-game basis.
Red Dead Redemption 2, as an example, can run at a little over 60 FPS on some GPUs but still manage 30+ FPS at 4K. That said, most games can run at 2x the framerate of 4K at 1440p, assuming the game isn't CPU limited.
The 4K 30 GPU requirement being lower than the 1440p 60 GPU requirement isn't that strange TBH.