We agree that this appears to be caused, at least in part, by a borer like Dogwood Borer. The areas of missing bark likely indicate cambium death (the loss of the tissues conducting water and sap between the roots and canopy), which if too extensive, cannot be replaced by the tree. Areas fed by those tissues will probably die back, if they haven't already, and wood decay might also set in since the wound won't be able to close-over quickly, if at all. (Do not coat tree wounds with anything, as that will not provide any benefit and may actually make things worse.)

What attracted the borer in the first place is hard to tell, but usually they seek-out trees weakened by stress like drought or injury. (Trees surrounded by lawn that have bark injuries from mowers or string trimmers are a very common target.)

The tree appears to be planted too deeply, which may have been a contributing factor. Unfortunately, this is quite common, as trees sold at nurseries tend to be too deep in their pots (or burlap wraps) well before they are sold. This can be corrected upon planting, but not many gardeners (or even nursery installers) are aware of this issue. The root flare should be visible, which is the point on the trunk base where roots branch (flare) off of the main trunk. This juncture should sit just at the soil surface, and even though young trees might not have a pronounced widening at that point, it's still easy to locate if the soil covering the flare is removed before planting. A garden hose is a good way to do this, though it can take some time and may be simplest to do if you can get the tree in a wheelbarrow so you're not dealing with soggy ground from hosing soil off. (Don't scrape it off with a digging tool because this could seriously injure the wood if it cuts into the bark.) The pages linked above provide more information about planting depth. Since planting too deeply can stress trees, that can be a factor predisposing them to opportunistic borers.

There is no pesticide that will remedy the situation, and unfortunately, the damage looks extensive enough in the photos that we aren't confident the tree will survive. If you want to wait and see how it fares, all you can do for now is to make it gets irrigated as needed; thus far, Maryland is still experiencing a notable drought. Dogwoods don't want to stay soggy, but they also aren't highly drought-tolerant.

Take off any stakes tied to the tree after 6-12 months (at the most) of use. The wire should not cut into the bark and should be lax enough to allow the tree to sway a few inches in any direction; staking too firmly will not benefit the tree at all, since swaying triggers more anchoring root growth and helps the trunk develop a taper that also provides stability. Unless the tree pictured is prone to being tugged-on by children or buffeted by high winds, it likely doesn't need to be staked at all and the stake(s) visible in the photos can be taken out.

If you decide to wait to replace the tree, let it leaf-out fully before judging how much dieback may have occurred. Sometimes dying trees still flower and may look like they're blooming normally, since all the pre-formed flower buds do is expand once they absorb water; they don't have any actual growing to do. Leaf growth starts out the same way, since the first leaves are already formed in those winter buds, but once growth kicks in, that's typically when plants that were too badly injured die and the tender growth collapses. Even though the tree looked fine last year, the borer whose damage is evident now was probably already inside the trunk. (The hole indicate it's since matured and left the tree.)

Miri