Just recently had it sprayed from professional as suggested for boost and growth. Could it be from that or something else. They are coming back next week.
It is very hard to give a useful answer when you provide scarce data (as also noted in comments).
My best impression based on what we have is that the root system simply for some reason does not have enough energy to support the whole plant. But it may recover (meaning, root system). Bare branches can be cut off, or even should be cut off. And water generously this and the next year. No fertilizer ever. No spraying ever. Just water. The plant will find its new leader by itself, do not bother helping it. Once you notice significant recovery, decrease watering to reasonable levels, and, again, no fertilizers of any kind. I wish you success!