The New Game+ mode in God of War Ragnarok is available on PS5 and PS4.
Studio Santa Monica details the New Game+ mode of God of War Ragnarok:
New gear, higher level cap, new enchantments… Once you’ve completed God of War Ragnarok, you can launch New Game+ to rediscover the story and start with more gameplay options. Your gear, weapons, including the Draupnir spear, and skills will carry over from your previous save. You will be able to use your entire arsenal from the very beginning of your epic. Please note that at the beginning of the game you will not have access to Sonic and Sigillary Arrows.