Quakers are an incredible social parrot , I have read that they will babysit unrelated offspring tho usually done by older siblings, they live communal like in condos in one big nest , and there are reports that if a pair nearby looses a partner they assist the solo parent raise the young. They are a fascinating species . But really no parrot likes to be alone .
While your two my always remain more distant friends , over time they can still develop a deeper friendship. Pikachu worked hard for 2 years to be friend my older quaker female who really didn't know how to be a bird , and become very close. Pikachu and Phoebe took near to 3 years to become bonded , deeply bonded and now live together .
I understand being fearful, I hope it is something you can overcome. Starting at first with more structured interactions will hopefully help. I like doing multiple short interactions at first . Trying to set up the interaction for success and avoiding known triggers , and limiting distractions , as well as other pets and people. You can work back to more inclusive later
And if looking at her is a trigger, working in desensitizing this. How I might do this , is get her out , chat a bit , then place her on a perch , walk a short distance away , look at her tell her she is a good bird , walk back over and give treats . Repeat this many times randomly through out the day , only once or twice at time and placing her in different spots for the next time , on thr couch on a chair and so thst looking at becoming linked with good bird and treats. And leaving her longer in spots before looking at her and doing this. Shaping behavior, going in baby steps , repetition and building off that is very effective with animals , parrots , critters .
My old sweetest rescue Penny, would get quite angry if she had to be caged longer due to me being away or life circumstances that has for ed me to leave her caged instead of her normal routine of being out. What she would do when I finally was able to let her out ,is launch screaming at my head or face to bite me. Because she wasn' t the best flier I could mostly avoid, and when I learned this is how she would likely act at first letting out I adapted. I talked longer with her before letting her out, and when I opened the door I walked away and turned my back . So the initial bombardment would be to the back of my head . After letting me know how displeased she was , moments later she was my cuddle sweetheart again. Tho occasionally she would also like to land on my shoulder and beak punch or beak slap my face. Then like at me and in my mind , let me know that was fir my own good now we can be friends again. Penny was the gentlest sweetest sweetheart parrot the rest of the time. In our situation this only happened after she had been left caged all day or for several days in a row. I never was able to eliminate the initial winged bombardment, but did lessen it to a screeching flyby ( 90% of the time ) by really talking to her and apologizing about being locked up for so long before letting her out, and by ore setting up yummy favorite foods in top of cage before letting her out, and being sure she was the one I let out first and gave attention to first . I just an a person who doesn't take all this drama to heart . I don't think I have ever shared this quirk of hers here before even .
My green cheek conure Ta-dah, will often come out of her cage in high energy high mental state , and interacting with her after just letting her out will definitely lead to bites and attacks. So for her also , I talk with her fir a few moments before letting her out. She marches around jabbering in her cage , I listen and agree. When that's calmed down a little, I open the doors and let her out. The climbs to the top of cage and displays and matches around mumble and I spend time talking to her till she calms down . Then because it's normally first thing in the morning I set out he vegg. On my later fo I go and get her to step up and have our morning hellos .
Think about, and find routine and ritual to help you two navigate situations that might lead to high arousal and bites. Doing your best to seet yourselves up for success