additional information is that so far, the tree has good leafage, and this is the only sign of doom. However, I recognize that it is early to tell, and the truth will become evident next summer likely

Maples tend to be thin barked and are often prone to sunscald in vulnerable locations. Generally, this is not a death sentence and the trees are typically able to live for years without further deterioration.

It is important to keep the tree well hydrated right up until the ground freezes. Well hydrated trees are less prone to scald.

Keep the area surrounding the tree well mulched to avoid the soil drying excessively.

Use no "wound paint" or other sealer but do continue to apply light colored tree guards in winter. Make sure they are not too tight so they don't trap moisture and allow good air circulation..

Yes, and to add:

The larger the wound, the longer it will take to encapsulate itself.

Next season when the dead bark loosens you can peel it off to expose the wound.

Careful not to damage living tissue along the sides of the wound.

It's a fast-growing tree and should close the wound up completely in a couple/few years and continue on without problems.