I read up to ch 20. I'm interested in the concept behind the evil in this manga, but I can't get behind the mc's vengeance. He wants to get back at the people who made him suffer, which I can understand. I don't think its a good enough reason to completely support the mc, however. Where it really falls apart is the way he involves innocents, causing them suffering, allowing them to suffer needlessly, and manipulating them, all for satisfying his own selfish revenge. In the end, he was consumed by all the evil directed at him. He was broken, and those who caused him suffering have already won. Nothing he does to them will change that. He has no personality. He was already broken by the time we learned of him. A shell for readers to place themselves in.
Now, keep in mind that this is just my opinion. From an objective standpoint, it isn't terribly written, though it isn't exceptionally good either. It may be better than some of the shallow, generic isekais, but its still not great. It tries to appeal to the reader's own desires, but It doesnt appeal to me particularly.
If you think that makes me soft or naive, I pity your foolishness. There are a lot of people that think they have some kind of darkness in them like no one else. They think the people around them are all sheep that don't have the same level of understanding. They are the ones who are truly naive.