1, 2: social pressures are powerful. she is a child and children aren't emotionally experienced. The 'disease' is a big, big part of her understanding of her identity. And the parts that we see about her are going to concentrate on the important and consequential parts of her life, so it isn't as if it is all she thinks about.
What I'm talking about is specifically moping about how she was mean to girls six years ago -- and she's still not over that. That's absurd.
Does she regret it? Ok. Then she regrets it and maybe apologizes or maybe doesn't. But if she's regretted it and hasn't done it since then it should be a resolved issue. Instead, we get six GD years of her moping about it, and unable to fully enjoy or live her life happily because of it.
And this is in the context of her having been very energetic as a boy. If that energy is her innate, unchanged nature, then she should have recovered it long ago, and just become an energetic girl. (Which would make this a totally different manga.)
And she's still waffling over "am I a boy, or a girl". This is despite her adapting quite well to being a girl and seemingly being fine with it. Yet the author still has her moping over this as well.
Seems to me that the fundamental issue is that the whole premise of the manga is "Ore" to "Watashi". So the manga is over when she finally commits to "watashi". So the author is milking it for as long as possible. (Just like how romance based stories milk the romance struggles endlessly to avoid terminating the manga.)
3, 4: like was this a joke? because isn't it obvious that that's an artistic license that's part of how manga culture in Japan convey that specific archetype of a person. the squintiness is demonstrating that the person is being a wise and kind person.
It's humor. Yes, JP manga and anime do this a lot, and it's something that manga/anime fans have to deal with. But my annoyance just bubbled over here. Especially for this grandma character, who has no reason to hide her eyes as far as I can see. (Squintiness indicates hiding the "windows to the soul" which may be for a good reason or a bad reason (e.g. they might be a psycho.) Though in her case it may just be that asian eyes are squintier than western eyes, and her eyes are squintty even for asian eyes.