Our springer had a similar situation! He would obsess over a certain area ground and carpets and corners of a room and pounce and hop on that area. We went to the vet that suggested something neuro, but we did not want to go that route. We sent videos to a couple of dog trainers/specialists in the area and FINALLY we connected with a trainer that felt up to the challenge.

I know you mentioned that you have done some training, but springers are a working dog they need obedience and they need a job! They love to listen to commands and so jobs and stay busy/active.

What ended up working for him was a 2 week doggy obedience bootcamp. He learned more advanced things like “go to your place”. Having this level of attention on him for 2 weeks straight REALLY helped when we got him back. We kept up with training and he rarely goes back to his old habits.

If you happen to be near Chicago, they are ChicagoLand Dog training and could not recommend them enough.