I have included the below so you can see kind of things you might be doing, but I would not do any of these exercises without talking to a qualified physiotherapist.
Perhaps the pinnacle of recovery from this injury for me was running again. More specifically cross country running to a speed and distance that matches my pre-injury self. For me this took 18 months, although I got close at around 12 months but had a set back.
I am not a physiotherapist, or a medic of any kind these are observations merely.
I may have overlooked fitness. In perusing my goal of running again I dropped all other exercise forms. This was a big mistake. Running 3 times a week, for a short distance (2 miles) was not keeping the weight off, and I let my weight climb to 16 stone. Which is 2 stone overweight for me, and border-line obese.
Running when over weight and unfit I think was a mistake. And lead to be injuring my heel again. I do not think it was the tendon, more likely the bone in the heel, as the pain was different. But it took around a month to go away, and I lost a good deal of gained symmetry. This happened around the 12 months mark.
These are the three ingredients that got me to a place where I could run well again.
Intense cycling helps regain the required fitness for running. Thrashing around the countryside on a bike of any type will help with fitness and weight loss. The latter of which may not be required. I will not mention numbers but to give an indication: keep you pedal rate high, attack hills, max out on flats. . . that kind of thing. I live in a hilly area and so climbs really hit the button for me. Cycle so you are screaming for breath.
Eat a diet that is nutritious, but does not result in wait gain. During months 10 to 14 I became obsessed with healing myself through eating lots of protein, in the form of eggs. My weight shot up, and this did not help at all.
Currently I am eating no more than 1200 calories per day during the week. Likely double that at weekend. Over 2 months I have lost a stone and a half.
Do not neglect you heel raising exercising. Although basic my bad leg is still weaker than my good.
As a 17 year old I used to run 2.25 miles in 13 minutes. I worked this out to be the same (speed wise) as running 2 miles in approx 11.5 minutes. I have added in a 1% performance drop per year to account for my age now and arrived at a target time for 2 miles of 14 minutes. So far I have managed this in 20 minutes, but I am running. . . and it feels very good.