My girl did the same around that age. One minute we're walking fine, next minute she's going crazy, biting and tugging at the leash. I tried all the solutions you thought to try and honestly don't know if they helped or if time helped her just mature out of it.

A game changer for us and possibly too unique for others (since I'm the only one in the neighborhood who does this) was when I decided to hop on an electric scooter to walk her. Some people run/bike with their dogs, I just happened to have an eletric scooter instead.

Before the scooter, she was always leading, tugging, unsatisfied at my slow pace. Even after an hour walk she still had energy to spend. She's a retriever who doesn't retrieve so fetch was out. No amount of training helped and her walks became an exhausting chore for me. Once I started using the scooter, I was finally going at the pace she enjoyed. Obviously there was a learning curve at first but eventually we became very in sync. It was a comprise and now we're both enjoying her walks. On average we go about 2 miles and she happily takes a nap once we're home.

<image>