I'm in zone 8b and used to cover my trees. Despite covering them, most of the covered branches did not make it through the winter. Overtrimming before winter is not something that I would do. Unless your tree goes inside as such practice weakens and could kill the tree during the winter freeze.
Every spring, I get new growth mostly from close to or ground level. Even when we have a very mild winter, loss of wood from main structure on young trees depending on variety is significant.
Having planted a whole bunch of trees that were thriving in pots in ground, I'm becoming more familiar with what usually has to happen in my zone.
The most important thing is to have lots of mulch around the base. It acts as insulation. Even if the top is lost, the tree in 70% of the cases does come back. Once the root system has a chance to get established, it should have enough energy to push some new growth and more than make up for winter losses. In almost all cases the initial tree was totally lost, if not the first winter, by the second or third winter it's all new growth. Most of my trees are not irrigated so I'm facing a double challenge as I spend the first few years watching them live and die with little progress. The research continues.