I think you're doing everything right for Bella! If her diet is good and she has plenty of chances to interact with her family and play with interesting toys in her cage, then that's a pretty good start at a great life. I think these plucky-cockies need occupation more than anything else. Give her a job to do. Hide her food so she has to search for it (eg. bury it under stuff or stick it tight inside a cardboard tube etc. Look up 'foraging' for better ideas.)
We have a large playgym suspended from the ceiling over our back sliding glass door. It's made of pvc pipe and has various things hanging from it (swings, rummage basket, large boing, ladder, cargo net etc). My Beaks (Alexandrines) don't use it that much, beyond perching between flights, but my Galah, Dominic, gets all his exercise on the playgym. Dom can fly, but not far and not often. Most of his exercise comes from clambering around on the playgym.
So, put your thinking hat on and see if you can devise ways to keep Bella moving about her environment. Things like a knotted rope can work well: birdie can climb up from the floor to a perch or across from one perch to another. Sadly, it doesn't work for Dom as he has large fatty tumours that prevent him using a knotted rope, but my other birds love climbing up and down. I use sisal rope of various diameters - the biggest is about an inch thick and
very hard to knot! LOL!
Another great occupation is trick training. Not everyone wants his bird to do tricks, but the training gives a bird something to think about and broadens his life experience. Don't dismiss it as another way to keep Bella mentally occupied so she forgets to pluck!
Of course, with cockies the best occupation of them all is chewing. They'll chew whatever you dish up: broccoli stems, carrots, celery sticks, paper, phone books, cardboard tubes, bamboo, wood, natural branches, plastic of all descriptions. You need to take care not to offer anything toxic or dangerous (eg. most bells designed for bird toys are absolutely NOT safe, so avoid 'em like the plague!) We have lists of safe trees to use here on the forum (you can use the search function to find them) and it's great to provide a nice hunk of tree branch with growing tips, blossoms and fruit for birdie to munch on. You'll be amazed how quickly one little cocky can strip a branch!
LOL! In the street up from us, the local flock of cockies has almost completely denuded the street trees of leaves and bark. I've planted some native trees in my yard to attract the cockies for a visit, but so far, no luck.
I do wish you well with dear Bella. She deserves the lovely home you're giving her and I hope you continue to make progress with her. You're lucky that she has some feather regrowth: my Dommie has lost all the feathers on his back and front because of long-standing follicle damage. We look forward to seeing some photos of Bella and Dom sends respectful squawks to his new friend.
