I can confirm, that this has to be done with a second player online. Playing with the AI does not work. Just start a side mission in the catacombs and play through it togheter. Unlocks after finishing the objective, no need to return to the catacombs.
Not sure, if it works with someone playing with buddy pass. I unlocked the achievement with a friend who owns a physical edition as well. Please confirm if someone unlocked it playing with a buddy pass player.