Image: UbisoftOfficial screenshot from Ubisoft.
This Joseph: Collapse trophy asks you to discover every location in Joseph's mind. It is an exploration trophy, so plan a long run that sweeps the whole map.
Walk the whole map around the Garden at the centre and visit every named place. Watch the map for areas still marked as undiscovered and head there before the final fight.
Do this on a low Mind Level with upgraded Traits, so you can survive a long tour. Unlocking Safe Houses early gives you safe stops while you explore.