I would continue to let her out and become more comfortable in new environment. How is socialization progressing, can you and others safely handle her? Parrots enjoy being the center of attention and are famously manipulative. Of course you must set limits and create the motive to self-entertain. I believe you've done that well with large cage + toys and playpen. Linking an informative thread of macaw adaptation with similar issues and variety of member advice:
https://www.parrotforums.com/thread...-advice-on-adjusting-to-life-with-ruby.89421/
Macaws infamously scream with the fury of a jet engine! You can never eliminate but behavior modification coupled with her enjoyment of "alone time" can mitigate!
I'm late to replying to this thread, but I wanted to chime in. First, welcome!! This forum has been an amazing resource for me. I'm not sure if you had a chance to read my posts that Scott shared about adjusting to life with Ruby, but I wanted to reach out as I know what it's like to be completely baffled by Ruby's behavior.
I watched the videos you posted and first let me say that she is sooo beautiful!! The sounds I heard on the videos are all normal vocalizations. I love when Ruby is vocalizing like that, as I view it as a precursor to her learning English. This is a complete assumption based on when she gets to vocalizing like that she starts throwing in the English she has learned, like "Good girl" and "Hi!".
Ruby also does what I call the "jungle call" where she SCREAMS, so loud that I can hear it outside my house (with all windows and doors shut) at about 50 feet away. Typically she only does this when she is out of her cage and I have left her room. When she does that, I know she is flock calling for me, and if I am in the house when she does it, I holler back and tell her I'll be there in a minute and she has begun to understand that and doesn't call repeatedly like she used to when we first brought her home.
Did she come with her cage or was her cage a new home for her? Do you know who she was with before you? Were there other animals or birds at that location?
She is in a cage very similar to Ruby's and I second the advice to attach toys to her cage. I know Ruby paces like that, but I drop the top opening for her to stand on and attach some toys so she can flip and hang from them. I also have a perch attached to the outside of her cage that she can sit on and tear up her toys. I think I posted some pics in my thread, but if not I'll be happy to share pics or videos.
Also, I didn't see what toys you have for her, but one of Ruby's best toy to occupy her is a sheet of newspaper!! Her previous owner's didn't give her anything to shred, and she LOVES to shred things. She will hold onto a piece of newspaper (no color) and just tear it into strips and then tear it into pieces. Is it messy? Yes! But I have learned to lay an old sheet below the areas she hangs out - it catches poops and toy shreds and then at the end of the day I pick it up, dump the shreds into the trash and toss the blanket into the wash.
Regarding new new nippiness - we are several months in, and Ruby still doesn't like to be handled much. Now, she will occasionally launch herself off her cage, and then she lets me get her. When she is away from her cage and hanging with us in the living room (I have my birds in a separate room) she allows me to handle her, but other than that - she will "bite". We have been lucky as we have learned her warning body language that she is about to bite.
One thing that has helped me to build trust is the target training. I have a clicker and chopstick. Birdtricks has some great Youtube videos on target training which builds trust in addition to teaching a "trick".
I have already been long winded enough, but I look forward to hearing updates on how things are going!
