You say it works in the menu? Then it must be in the other levels where you call the save game is not done correctly in the blueprints as I’ve no issues using the save game accross different levels.
Also I would move the save logic out of the pre-construct event into something a bit later like begin play in case that is causing the issue. Also did you try cloning the same BP logic from your menu BP in the other levels to see if that works.