My in laws have a really stinky lab. He has a systemic yeast issue that's not quite fully under control. For years, my MIL was bathing him with oatmeal shampoos which turns out was like the worst thing you can due to treat yeast. We found this shampoo a few months ago and it has really cut down on the smell
Zymox Enzymatic Shampoo and Conditioning Rinse|Dog Skin Care
Eta - you should really get your puppy checked out by a vet though. Unless you're really sensitive to dog smell, a lab, especially a 3 month old puppy, should not be that stinky.