Even though I've seen shows that are objectively worse, this is the first show that has made me want to pull my brains out through my ears with a metal hook. It seems this show has been decently well received, and I myself can't quite express what it is about this show that irritates me so much, so I can't guarantee everyone else will have the same experience. But if I had to narrow down just what is so insanity inducing about this anime, it's the fact that she's in her twenties, but only the audience knows. I've never moreso empathized with Candace from Phineus and Ferb, the feeling that you know something that the writers are trying desperately to gaslight you into thinking doesn't matter.
You see the problem with Myne is that the authors seem to have a hard time deciding whether or not she's supposed to have the mental capabilities of toddler or a college student. She has all the knowledge of an adult but still acts like a baby, and within the logic of the show she should be internally a fully functioning adult. So how exactly is it, that I as the audience am expected to go "Aww" when she jumps into a man's arms going "DADDY I LOVE YOU" when realistically she's only 3 or 4 years younger than him and also- HE'S NOT HER DAD??? She's skin walking as his frail and sick 5 year old daughter?! What? How is anyone okay with this? Or when she tells a group of seven years olds that she'll never forgive them after they ruined one of her attempts at making books... That's not 23 year old behaviour. Not to mention the time she starts blushing profusely after a 7 year old flirts with her. But it's also impossible to forget that she is in fact a full grown adult, because the writers keep reminding us how smart she is for a 5 year old and how mature she acts for her age.
Relating to this issue is the following scenario. Imagine you go into work one day and one of your coworkers is asked, "what's 7+8?" and he answers, correctly, "15." Everyone in the office looks up and gathers around him. The manager comes out of his office and congratulates him on solving the question, and offers him a promotion on spot, all the while your coworker smiles smugly telling all his admirers that it was easy for him and he's done harder problems in the past. That's how it feels watching this show. Look! Myne can do long division! She's a wonder! She's a miracle! The second incarnation of the lord himself! Am I supposed to be impressed? She's in university, it would be crazy if she couldn't do basic arithmetics. At least her isekai peers generally still have skills that go beyond what's expected of the average person, for example in Doctor Elise; even on earth it's considered impressive to be able to cut a highly sensitive explosive out of a man's flesh without it detonating, or in Campfire Cooking in Another World; most of us can't cook well enough to tame a legendary beast. But Myne doesn't have any of that. Myne is annoying, weak, a little creepy, skin walking, and every character in the show is convinced she's god's great gift to the world... Lovely.
All of the other characters aren't even lucky enough to be considered annoying, after all, being annoying could technically be considered a character trait and they aren't allowed to have any of those.
In terms of redeeming qualities, there are no redeeming qualities- I mean the op is pretty okay? Does that count? The characters are terrible, the animation isn't great, the plot... there is no plot and the world building is pathetic.
I know the score I gave it was a 3 (much higher than what I felt like giving it), but that's because I know most people won't feel as strongly as I do and ultimately reviews/ratings are there to help other people decide whether or not the should watch a show. However if you've somehow read to this point in my review and agree that it doesn't sound appealing to you, I couldn't possibly recommend you actually put yourself through it. If all you want to see is a story about a resourceful child (actually a child) navigating a difficult world I'd much rather recommend "The Weakest Tamer Began a Journey to Pick Up Trash" instead, it's not perfect but it doesn't make me wanna throw my laptop out the nearest window.