the one ring dilemma is just amy's entire life.
amy has an alien virus in her head that thrives when its host is placed in high intensity situations - and she has essentially been using it to heal people at hospitals for her entire career as a hero. it cost her everything and she even her feelings of responsibility to the people she was saving faded until all she felt is bitterness and resentment.
the shard isn't like... possessing her or anything, but amy's shard is a lot more present than a lot of others according to word of god. ultimately amy kind of failed the one ring test by abusing her powers in a series of moments of impulsive and deeply awful choices made in the midst of an extensive psychological breakdown. but! she lasted two years
on the flipside she hates her power and wishes she could be rid of it because it's both so much responsibility and so much work. so i think she would actually survive the ring challenge because the idea of having MORE power would make her want to throw up actually
damian would be immune through sheer stubborn force of will and pride. he's very good at isolating what is and isn't real whenever his free will's been tampered with. in batman vs robin (terrible comic btw) he gets possessed by an ancient god with a grudge against his father, and he later explains that he was still on some level aware and acting against
said ancient god while being fully in his throes. and then dc vs vampires in which he became a morally neutral vampire hellbent on killing other vampires and protecting his loved ones - also helping other vampires resist the lure of power and hunger.