I personally don't really feel sorry for her, but I will say that the string of unending torture she goes through just starts reading like victim porn after awhile--especially once her mom collapses, ends up in hospital, then renounces Miyuki, and Miyuki is left alone in her house shunned by everyone--unable to eat, doesn't bathe, goes full shut-in and it just goes on and on and on like this with her going insane from depression, guilt, regret, and isolation.
I'm not all caught up on the WN at the moment, but last I left off when the Prime Minister was getting involved through Ai's dad's disastrous political suicide, it was still ongoing and I honestly would prefer she just disappear from the narrative, rather than be locked into that monotonous hell of "checking in on Miyuki and ....yep, her life is still shit. More at 11."
I'm not saying she needs to be given a chance at redemption; maybe a hard-restart like moving to a new city and changing her name or something. But she just needs to be allowed to leave the story, if all she's doing is wallowing at rock bottom with no further plot relevance whilst taking up narrative space from other goings on.