I definitely wouldn't ever suggest a smaller cage to anyone - but it's a good question to ask.
It sounds like a mixture of hormones, personality, and really still being new to the environment and adjusting.
Hormones, you know about from all these other posts.
Personality - some birds like toys, and some don't. Some like very particular kinds of toys. Some don't like toys as babies and grow into them, some the opposite, and some go through phases during the year. My Mango, he started out not really know how to use toys and believe it or not we had to kind of teach him how to play with some of them. Now he goes through phases where he's enamored with some toys for a while, and then doesn't care. He's just not a chewer, so chewy toys don't work for him. He just doesn't seem to be interested in playing too much. But we fixed the probem of potential boredom with foraging toys - and he gets about 50% of his diet through foraging toys and methods. So, for the bird that doesn't find just the joy of chewing to be pleasure enough in and of itself and motivating to work on a toy.........I always, always, always suggest foraging. There's tons of toys for that and little tricks and things you can make or do yourself. That will definitely help to get rid of any excess energy that may be coming out as aggression, too.
Lastly, still adjusting. I would give it a full year before you can start to predict her behaviors and before she's settled in. More than just a couple of months. Between now and then she'll go through lots of phases and adaptations and seasons. My vet has counseled this to me. So I wouldn't worry too much about specific behavior patterns yet until you've seen things play out over 12 months and all of the seasons, etc - and then you'll both know each other well enough to identify specific personality traits, preferences, schedules, and make decisions accordingly.
P.S. - we don't cover the cage at night, but we do have a full-spectrum bird light set on a timer. He sleeps absolutely fine, and since we have a studio apartment he's around us, and our noise and schedules, all of the time. Some birds need covering, some like it, some don't like it, some are indifferent. We tried it with him. He's indifferent. We did, however, just lengthen the time that his bird light is on to replicate the longer days of spring/summer (for whatever that information is worth

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