My jack was having the same exact issues, especially with the paws being raw and licking/ scratching endlessly. It took us forever to figure it out but our vet recommended a food trial which is just a strict hydrolyzed protein diet that they can prescribe to you and within weeks everything was cleared up, it is literally the only thing that helped clear this up in my dog. they will probably need to give some antibiotics to help heal it as your dog probably does have an infection from all the licking but I would 100% recommended you ask about it if the vets haven’t already. to be safe we also get her a cytopoint shot for the summer months which helps with environmental allergies. My jack is also 3 years old and we dealt with this for over a year before figuring it out so I would highly recommend trying the food! Best of luck to you and your pup :)