How old is Nix now. I only ask because from what I have read is you need to expand the area the dog I guess in a sense calls its territory due to the fact they wont use the restroom where they sleep its a standard size bedroom.
She's 16 months old right now, and she came to live with us when she was 4.5 months old. However, from the very start she had access to almost the whole house. We have about 110 m2 in total, divided in three floors. She had access to the ground and first floors. However, for the first two or three days she didn't know how to climb the stairs, so she was restricted to 40 m2 at at time. She'd be downstairs during the day and upstairs with us when we went to bed. Initially she would do her business in the corridor, but in about three or four days she was consistently relieving herself outside. We did nothing special other than praise her with treats when she went outside and clean her inside messes immediately after they happened with a mix of water and bleach. We never scolded her (maybe just a panicked "Nooo!" escaped us once or twice). Although our first idea was for her to sleep in the upsairs corridor, she slept with us (on the floor) on her first night and after a while we felt sorry to kick her out, so she has stayed.
True, they usually don't relieve themselves where they sleep. The few times Nix has had an accident, she's relieved herself in the downstairs corridor. Ironically, during the day she is usually there. In the summer, because it's cooler, and also because she waits for us (or my husband) when we're away.
I am not sure with how she acts when we aren't around seeing as I have a family member at my house when me and my wife are working or away.
In a way this is good for her because she's not lonely, but I believe you should try to let her on her own for small periods of time at first. Try to walk and tire her out before you leave her alone, and you could also leave her with something to chew or a toy to keep her entertained. That's what we did with Nix. Even if you're careful, there is the risk that she'll destroy something while you're away, so keep your valuable things out of her reach. In our case, I consider that the losses have been minimal: a scratched wall and the lower part of the door frame is gone. A couple of times she also ripped papers apart. However, this usally happened when we were away for extended periods of time (from four to six hours). She now sometimes barks when we leave, but luckily it's not always and by the time we get back (sometimes we're away for just 20-30 minutes) she has stopped.
When she is hungry she gets pretty destructive with things like her water and food bowl, but we do not feed her because we are trying to keep her schedule. We do however take her outside for some play time.
Mine also acts in weird way to catch our attention. As a puppy, I remember she sometimes would place her paw in the water bowl, scratch it and make a mess. What we normally did was to take away her water bowl for a while. At one point she stopped doing it. Similarly, she sometimes played or chewed her food bowl, but we'd also take it away. Fortunately, she no longer does any of this though.
I did notice however when she is in her area she is either looking for us if we run in the house or laying down hiding in a sense waiting for us. For example if we put her down to use the restroom and go inside to get something or fix her food bowl by the time we come out she is hanging on the pet fence we use to block her area.
I think this is standard GSD behaviour. They are loyal dogs who want to be aware of everything that is going on around them. So they try to get as close to the action as possible and can get frustrated if they can't. But they also have to learn to be patient and wait.
As well as if we are not watching her and she poos she will eat it if we are near her she will do her business and walk away
If I understood correctly, she eats her poo when you're not watching? I know some dogs do this, but sometimes it can be due to some kind of nutritional deficiency. Make sure you're giving her a balanced food.
We want her to be a house dog so we eventually want to give her some freedom to walk around the house at a later age, we just would rather do it slowly like maybe instead of giving her the whole room buy a pen and make her use that for a while. If that also seems like a good plan. our goal is to get her used to the whole house in small doses instead of trying to let her out and walk around and stuff.
I think GSD are great house dogs who love to be around their owners. This will probably work, but as I explained above, I have no experience