I haven’t had any trouble with Working Together being abused, though I have more stringent requirements for what constitutes Working Together than I think a lot of DMs have. As per the usual task resolution system, to make a check in the first place, a player needs to describe an action in terms of what their character is trying to accomplish and how, and that action needs a chance of success, chance of failure, and a cost or consequence for failure. In order to grant them advantage on that check, another player needs to describe an action in terms of what their character is doing to help (the goal is already established as “make it easier for the acting character to achieve their goal” by the nature of Working Together.) But the thing is, the action needs to be something that could reasonably help the other character achieve their goal, and isn’t simply doing the same action independently. “We’re both looking for traps” not only doesn’t establish an actual approach, but is also just two characters each doing whatever thing they’re doing to try to find traps, not one character looking for traps and another character helping them do it. When the Rogue is trying to unlock the door using her thieves’ tools, there’s really nothing anyone else can do that would help her with that (and no, words of encouragement and/or shoulder massages don’t count.) Lifting something heavy? Sure, that’s something you can work together on. Trying to recall a piece of information? Sorry, you can each try to remember it, but you can’t really do much to make it easier for one person to remember it.