Just a few few thoughts based on my experience with this species, though not with this particular cultivar:

In zone 4 this tree might not be hardy unless it is in a very sheltered location, based on my experience with other forms of Kousa dogwood/Cornus kousa. I have two unnamed Kousa dogwoods, and the one in a more exposed location has had severe damage with a lot of the wood killed at -23F. while it has regrown, it is not a very well-shaped tree.

While I have no experience with this cultivar, I have yet to see a Kousa dogwood that didn’t develop nice color, though it tends to be quite late. Mine are the last to develop color in my yard, and the last to drop leaves. In your zone 4 (though you haven’t given a location) snow may arrive before yours develops color, or you may get damage from early wet snow weighing down branches that are still fully leafed out. Also, IME, fall color is often dependent on tree age, location, and the weather in a given year, so what you see in images may not match what you see in your garden.

thank you NHBabs. I'm zone 4/5 in ON, CAN. Many but not all z5 survive here.