I see what you have is Hers's maple (misprinted as Her's maple on Wikipedia, I'm right, Wikipedia is wrong). It has at various times been considered a separate species, A. hersii, and also a variety of Acer grosseri, but I think recent thinking is that all these are subspecies of A. davidii, the classic snakebark, despite the very obvious differences. I also have one, about 10 yrs old. I'm guessing yours is about 5 years old?

There are two potential problems with the damaged trunk, one is mechanical strength, and the other is transfer of nutrients. Also, since the value of snake-bark maple is often enhanced by having fairly low branching, to show off the stripes on multiple low limbs, which are kept clear of leaves low down, you have lost an aesthetic feature of the tree.

I have an apple tree (bear with me) which obtained a bad canker fairly low down on the trunk at about 4 yrs old, greatly reducing the transfer of nutrients, as only a narrow part of trunk was undamaged where the canker was located. The result was that the upper tree just couldn't grow. What I did was saw off the tree below the canker (but above the graft) in winter to see if it would regenerate from there. And it did, very well. But I also planted another tree in case it didn't. The sawn-off tree took about as long as a new-planted tree to get back into fruiting, but resulting from being longer established in the ground is better established and larger than the tree 4 years younger.

If you cut off your maple below the damage (wait till it is dormant in the winter), and it regrew, you would probably have the advantage of increased branching, low down, which will then better show off its snakebark, provided you later trim off any low leaf-bearing growth. This depends upon it having dormant buds, in the way that some trees, eg leyland cypress, don't. My tree does seem to have dormant buds, because it occasionally sends out little leaf-bearing twigs low down on the tree. So I am guessing, but not sure, it may be able to regenerate if you chop the top off below the damage this winter.

The mechanical problem is that in the long run to re-establish its strength, ie avoid being leggy and prone to wind, it needs to be flexed by the wind. In the short run you need the stake, but at some point it needs to be freed to flex in the wind to encourage it to grow as needed. If it can't regain sufficient mechanical strength, it may then fail to survive anyway.

In summary, I think your tree is unlikely to be an attractive tree in future as a result of the damage, so you have two choices: (1) replace it this winter (2) try the drastic remedy I suggest. You will choose the former if you don't hvae the patience, and don't have the space /location for a reserve tree.

In the case of apples, I'm a strong believer in planting 1st winter trees (bare root "maidens"), because in the long run they establish so much better. You clearly planted quite a large tree. I wonder if it would establish better if you planted a younger one?