Your in-ground pomegranate roots will survive the winter.
The problem is any late spring freezes that might occur after leaf-out. That’s what shocks the plants - when they are vulnerable - and kills them here in zone 6.
Zone 7 and higher a few varieties can take this abuse and survive/fruit… such as Salavatski. But it can easily kill them just as well too.
I’ve resigned to keep them in pots in the basement through winter until all threat of late frosts has passed.