GSD's are not always easy dogs, but when you put the effort into training and working with them they become seriously amazing companions. Set rules and enforce them, look up NILIF to start and find and stick with a good trainer. Set up a schedule as well which include lots of physical and mental exercise and you'll find a much happier dog.
There's very rarely such a thing as too late to train. My first personal dog was a 8 year old cocker spaniel rescue who was going deaf, in a matter of weeks he was fully trained in sign language so I didn't have to rely on verbal commands. So don't despair and set limits which may not be true
I personally have a WL dog with high drives and energy and I'm gone from 6 AM to 4:30 due to work but I make it work and commit my extra time to training and exercising, I find it fun and relaxing to spend time around them and on the days I leave in the evenings I simply spend as much time as possible before and after