How to train an over stimulated dog who doesn't care for treats or toys?

Hi. New to your account and really happy to be a follower.
I have a 18 months old male doberman who is very good at home and follow all the commands. But when out side he is always over stimulated, less engaged and doesn’t care for any treats or toys. No matter how high value it is. Also he is fearful about many things like traffic noise, new place etc. If I even take a new road to walk he will whine continiously until we get back to the area near our house. He used to pull a lot but now after lots of training he walks fine but he is not engaged much when outside. Always over stimulated. Feels like he is two differnt dog when at home and when out side. I take him for 2-3 walks (each 30 -45 minutes) and use puzzle toys, different games and short training sessions at home for mental exercise.

  1. How can I help him become more confident?
  2. When he is not interested in any food or toy what to use as a reward for training? Only praise is not working I think.
  3. what to do when he whine continiously to avoid anything?
    4)Is there any way I can build food drive or toy drive for training session out side?