I tried to do gymnastics, spent about an hour a day on it for two months. There were improvements, but small (I began to see two more lines, in total - five). Then he abandoned this business, his vision began to fall. The advantage of gymnastics is that it helps to relieve stress, allows the eyes to "rest". Therefore, I advise you to try, especially palming.
Vision restoration is a myth. But some improvement is possible, since the tension of the ciliary muscle, which is responsible for focusing the lens, will decrease. Exercise helps to relieve muscle hypertonicity that interferes with focusing on distant objects.
With exercise, you will feel less fatigue and discomfort after prolonged focusing on near objects.