"Oh, scaramouche gets away with everything"
"He's just escaping his crimes, he's not actually repenting"
"Why'd they have to make dottore the real evil villain behind everything?"
"He's a good guy now"
These critics all miss the point of Inversion of Genesis, and Scaramouche in general.
Small note: If you are coming here from reddit, then you have already read most of this. However, I have added an extra paragraph at the end.
Inversion of Genesis, primarily, is a story about how trauma disrupts the internal story of people in a way that they fail to create proper structures for which to engage with life. It's also a story about the perfect suicide, and why even that isn't good.
You also have to understand Scaramouche first. He's primarily emotional, but views it as a terrible thing due to the ways he's been hurt in the past. Despite that, he physically cannot stop himself from caring, and his goal has always been suicide, although not the suicide as we know it. You see, when Traveler warns Scaramouche that the process of turning him into a god will destroy him, he's not seeing that as a bad thing, it's one of the perks. He's tired of feeling because the world has always punished him for having feelings. Whether it's Ei (yes, she's at fault), Dottore, the Fatui in general, trauma has defined him and has ruined his ability to create a healthy story to define himself. He is a shell filled with the one thing he hates, which is why he turns that pain on everyone else in order to punish them, too.
Some people may read this and go "That isn't an excuse for his evil deeds. He still made the choice to do evil."
That's not what the story is about, and you're reading it wrong if you think it is.
The story refutes this anyways

Scaramouche, after failing to commit suicide once, is arguably at his lowest, at least in the game. He's a prisoner held under Nahida, he lacks his divine power and support from the Fatui. This is the catalyst that leads into his second suicide attempt. When he learns that Dottore was the person responsible for Tatarasuna, his worldview instantly shifts. No longer can he say that the world punished him for having emotions, because it didn't. Yet, despite this, he doesn't immediately fly in a rage to avenge Niwa and try to kill Dottore. He instead sacrifices himself, thinking that removing himself from history will allow his friends to live full, happy lives. This is the deepest insight into who Scaramouche is as a person. He is a caring person who was forced by the world to be cold and abrasive. He has to look for excuses to care, namely "value exchanges". That's why, in spite of all his evil deeds, it's impossible to call him purely evil.
Wanderer is what happens when Scaramouche is erased from reality, and the trauma that defined him doesn't exist. He is aimless, helpful, empathetic. He bears no guilt or shame. Despite this, he still desires the truth. Why? Well, it's because he needs to learn to integrate the trauma back into him. His brief time as "Wanderer" reminds him of the worldview that made him happy, yet he still needs to synthesize the worldviews. Suicide can't help him, he realizes that now. Thus, the only option is to live. To live is to suffer with the unbearable guilt that he can no longer rationalize away. To live is to open himself up to a thousand more cuts and pains. Yet it's clear that living is the only thing that he can do. It's the only thing we can do.
With Nahida by his side and a new community of people who value him, Wanderer can start to rebuild his fractured mind, and remove the story that Dottore and Ei's trauma forced upon him. He is a man whose principles are at odds from his personality, and the dissonance between the two caused him great pain. Now he has the option to change his principles to his personality. He is not guiltless- quite the opposite, in fact. He alone bears the guilt of what happened in Inazuma. He will allow anyone to bear their own vengeance upon him if they so desire, but it helps no one to do that.

To put it simply, to talk about Inversion of Genesis as though it is about Justice is a misread of the story. That's not what the story is about, though it does touch on those concepts. Inversion of genesis is well written and Scaramouche has an intricate characterization that is sadly lacking in most of Genshin's cast, though I understand why that is. Due to the way the game needs to generate profit by introducing new characters, it’s difficult to invest into long-running stories that may not end up paying off in the end.
Wanderer’s first banner, with Itto’s second rerun banner, earned an estimated $27 million on iOS devices in China. Other estimated figures put this banner at 11th place, and among male character banners, fourth. Among male exclusive banners, Wanderer scores a solid 2nd place, losing to Venti’s first banner. No doubt he is currently one of the most popular male characters in the game, a rarity for gacha. Hopefully, this will encourage Mihoyo to invest into more long-term storytelling.
Thank you for reading!