Any thoughts on my new puppy’s mix?

I just adopted the cutest little bean and the shelter told me he’s most likely a dachshund mix. He is 3 months today and was 10.1 lbs when we weight him this morning. 2 weeks ago when we got him, he was 7.6 - he’s growing a lot faster than I imagined he would. I think he may be mixed with Rottweiler or Doberman but I’m not sure! Anyone have any guesses? Or similar looking doggies to mine!?