All things being equal, yes, they should survive. The root system will not be affected and that will let them survive. You could always wait until they bloom and a week or two later prune them.

Consider transplanting it to another spot long term as this pruning will become yet another chore you have to do every "x" number of years. A dwarf oakleaf in that spot may be worth thinking of too.

Funny story: I saw someone once who had one planted in the wrong location. As the plant grew larger, the oakleaf got in the way of people who took a tour of her garden. When I participated on one of these tours, she had placed chicken wire fence around the oakleaf real upclose tight to force all growth higher up. Looked weird to me; said she was going to prune it in the summer.

If the standard oakleaf, they are not overgrown at all! Hydrangea quercifolia gets to be a large shrub -8'x8' is not at all uncommon and larger is possible.

If your oakleaf hydrangea is out of size for its location, suggest you investigate a dwarf variety. Replacing with a more compact form would be far preferable than pruning to size.