How long does it take to restore vision from -2?

Try the simplest daily eye complex. It works. Experience in working with people for 12 years.
1. Horizontal movement. We avert our eyes to the left, translate to the right, return to the left again. This is one movement. We do 36 such movements.
2. Vertical eye movements. We raise our eyes up, bring them to the eyebrows, lower them down to the base of the nose and again raise them to the eyebrows. This is one movement. We do 36 such movements.
3. Rotation of the eyes counterclockwise, tracking the smoothness and circumference of the movements. Slowly rolling the eyes 18 times counterclockwise and then 18 times clockwise. Film Every day, in the morning.
And we add water massage to the eyes when washing. The palms are boats, we collect cool water in our palms and splash 8-10 times into our open eyes.

If we are talking about exercises for the eyes, then, as far as I know, they can "return" only a limited number of units, and the effect will last only as long as you do these exercises. When you stop exercising, the effect will go away.

Personally, I did laser correction (from -3.25 ..- 3.5), it takes very little time, 2-3 hours the operation itself with all the necessary procedures , and a couple of days to recover after. But I'm not sure that at -2 it is worth doing it, and they may refuse if the value is unstable.

You can basically do nothing and wait until hyperopia begins to develop with age, there is an option that mutual compensation will occur.

In any case, I recommend that you consult an ophthalmologist, and preferably two.