Whenever there is a change in behavior you should start by making sure there is no physical or health reason contributing to the problem. You have already identified one reason: she behaves worse when she is tired. Since she now is a year old, she might also be less tolerant of rude behavior; it's a very normal change when dogs reach adulthood. It's also possible she might be feeling unwell or uncomfortable. I wonder if the harness incident happened because she was feeling a little sore, or she feared the harness might pinch her hair.
The next question is whether she is resource guarding. Dogs sometimes want to defend their food, treats, or toys. Sometimes they also to defend their beds or the place where they are resting. Sometimes they even defend their favorite people. Punishment is the wrong way to handle resource guarding issues. The dog becomes more insecure and attaches more value to the item they are guarding. Then the problem gets worse. I won't go into more detail here. There is a book called
Mine! by Jean Donaldson, which provides a lot of information about handling resource guarding.
Whatever the reason, I would start upstream from where you are now. Growling and snapping is a form of communication: she is telling you she is uncomfortable with what you are doing. It sounds like she has excellent bite control. She certainly could have bitten you if she wanted; instead she has simply warned you. That's actually very good. What you need to do now is listen to her warnings and figure out how to make her more comfortable with your requests.
Pretend she is a 350 kg pony. Nobody picks up a pony. If you want a pony to move, you need to persuade the pony to move itself. You can persuade a dog to move itself by teaching the dog to Touch your hand. Turn Touch into a game you play with her. I play Touch on my bed and on the couch. Since I have played Touch so many times, my dogs don't mind moving when I ask them to. They don't think they are losing their place on the couch. They think they are getting up to get a treat as part of a game. Kikopup has a
good video on teaching Touch.
When she has something she shouldn't have, let her keep the item if she can't hurt herself with it. Kleenex isn't dangerous. Socks aren't dangerous. Your underwear isn't dangerous. You can retrieve them later when she loses interest. Don't worry about messes. Right now it's more important that she trusts you. Don't steal her treasures.
Of course, some things ARE dangerous, and she can't keep them. She can't keep something like a medicine bottle or a kebab skewer. Therefore, you should also teach the command Leave It. I made a
post in another thread about how I would teach Leave It. Make Leave It a game before you ever need to use the command to take something dangerous away from her. And, use Leave It as rarely as possible.
