It sounds as though your experience with Achilles tendonitis has been a long ordeal. As you have been doing, the best place to start with this kind of injury is with an orthopedic surgeon
who can then help coordinate physical therapy. From what you have said it sounds like you have done an extensive amount of physical therapy that has not fully gotten you back to your old baseline. Unfortunately, with some orthopedic injuries it is not possible to get back to your pre-injury baseline. However, there may still be some additional options you can try.
First, you can always go back to your original orthopedist and physical therapist
to see if they can give you a sense of whether or not this injury will fully resolve. If you would like to pursue a second opinion, your primary care physician should be able to help you select another physician or physical therapy group to consult. Depending on where you live, there may well be an academic center specializing in orthopedic issues where you could see a specialist.
Second, if you have not seen a physiatrist
(physical medicine and rehabilitation specialist), this may also be a good referral option. PM&R physicians work with patients with rehab needs, whether from injuries or from lifelong conditions such as spinal cord injuries or cerebral palsy. Many PM&R physicians may also be able to help you connect with alternative medicine options for relieving chronic pain or musculoskeletal problems. Your primary care physician should be able to help you find a physiatrist in your area.