I got this on NG+3, though it may be possible on NG+2. This doesn't require upgrading each item. You can get blueprints from chests, more commonly from silver chests. You will want to use the soul shop to increase the amount of blueprints that can drop, using the top most option. You can get the souls needed by beating bosses (100 per), getting a new trophy from a scar, or from npcs after chatting with them (500 per).
My method for farming chests was ascending the Sun Tower as Barbarian (high health plus aerial spin attack) with flight enabled and retiring my hero once I got all chests.