Actually use the apples and bananas to your advantage... getting to eat new things is like playing chess, you gotta out move them and keep a step ahead

okay, I don't play chess, but that sounded like a good comparison...
Don't give her apples or bananas on their own. Make up a small chop mix, try different shapes of pasta, maybe do a sticky rice (no clue why, but Ivory loves sticky rice), or try the Asian noodles that are made from bean. You can even pull the food from your daily menu, just pull before you add salt or butter, pepper is okay for the birds. Then pick a veggie, if you're having something, go with that for starters. Kinda mash up the rice/pasta/whatever with the veggie and also banana or apple. Kinda make sure everything is coated or has apple/banana on it. Even go so far to put the apple or banana thru a blender.
Birds are also big on grains and beans.... we do lentils alot everyone loves lentils - either cooked or sprouted. Try barley or chick peas... baked potatoes are usually fairly well received, tho surprised to see you have sweet potatoes on the no list! Did you cook the sweet potatoe? Try it cooked to different degrees, just somewhat so its still little hard, then completely so its an easy mash and apples would mix in perfectly!
Another weird thing with birds is to try different shapes... Mango may not like a slice of carrot, but thinks slivers are wonderful... or try cutting stuff into cubes.
And when you find stuff Mango will eat, just keep adding it to something else. And the best advice anyone can give you... don't give up, just keep offering. Ivory had never in 4 years had fresh foods and when she first came home it was beyond frustrating. But now she'll eat most things. Funniest part... as a white bird, the first big hit with her was beets!!! Yep, messy red-purple everywhere beets...
And I've mentioned to others, you are now Mango's flock... and a flock eats together. So bring a playstand closer to the table when you eat and offer Mango some of what you have. If you're more of a nut like me, you can make your bird a plate and bring them to the table, but be prepared for your bird to investigate what is on everyone's plate.... I make her a plate of her own, but then usually have a little pile on my plate so she can feel like she's 'stealing' the food, somehow it tastes better when you grab it and run like a chicken across the table to eat your 'forbidden' morsel... thus the chess game analogy...
Good luck and don't give up!!! Mango will eat more as she settles in and gains more confidence in her place in the flock. Sounds dorfy and silly, but its true.