Many people are aware that puppies go through a "fear period" where they are particularly sensitive to experiences, and that it is important to protect them from having bad experiences during this time. Did you know that there is a second "fear period" during adolescence? As dogs become sexually mature, they go through another imprinting phase where positive and negative experiences become especially salient to their learning and ultimately end up shaping their personality.
This is a great time to keep training and hand feeding high on the priority list. You will probably see breed traits become exaggerated in your dog, and if these are traits we want to downplay, you should prevent their rehearsal.
It's a great time to reward behaviors you DO want to see because rewards are even more meaningful. It's also important to remember that while your dog may look like an adult, they are very much incapable of regulating themselves. They are, in fact, in a "conflict phase" where they will certainly be pushing boundaries and taking risks.
So keep your cool, have patience, and help them regulate. Having a daily routine will add predictability for them, which creates safety, connection, and regulation. This will also help you to cope with mood swings, zoomies, and any regression towards puppy behavior.
If you are having a hard time creating the right balance of management, exercise, and routine, it might be worthwhile to speak with a trainer! It is a time when your patience (and very sanity) will be properly tested, so getting support is always a good idea. You and your dog will come through this phase stronger if you work as a team and work on strengthening your bond through play and communication.
Resources: The JRH Academy