I just finished my first play through and a popup appeared saying I had unlocked game plus, but I am unable to figure out how to activate it or it's not working. I created a new game save after the pop up appeared, then I quit to the main menu and started a new game and there was no option for game plus. The only options were to start a new game from the beginning. The game is updated to v 1.22.

When you start a new game from the menu, 1 of the options should be New game +.