Here's a great post on the OPM detractor Reddit (OPM Folk) of someone explaining their disappointment with Garou's characterization in the manga compared to the webcomic and it's a good read.
One part that it brings up that I didn't realize ,probably due to a lack of real interest in the manga anymore, is that Garou didn't have a real turning point.
The manga has a way cooler fight because there are bigger explosions and they blow up moons, stars and even Jupiter itself. The feats are way cooler. But these are erased by time travel. So that fight never happens in the first place. In fact, in the eyes of everyone but the reader, Garou ends up being defeated by an unknown entity. There is no lesson from Saitama in the manga. He just thanks him for helping Genos and King. So Garou doesn’t get his worldview questioned. The readers aren’t given an interesting foil to Garou’s goals. Saitama wasn’t the one to defeat Garou, so Garou didn’t develop that deeper connection to Saitama either and vice versa.
This part is why I wanted to write this rant in the first place. How Garou is treated at the very end of the MA arc, and how he emotionally responds to everything that transpired. In the webcomic I love the change in Garou. After being defeated and hearing these words from Saitama, you can clearly see the effect it has on Garou’s emotional and mental state. He is dejected, numb, and does not know what else to do. He was so close to achieving his life’s goal, but had it cut short. These feel like real emotions, and a real reaction to someone who had their entire raison d'être eliminated. He says he has no reason to live anymore and I believe him. The cocky Garou who thought he was better than everyone and everything is no longer here. After all, he was just humiliated and he knows his plans for absolute evil and terror would never work. Even when Bang is punishing his ass, he remains indifferent. He's so empty that he doesn't bother retaliating or making witty comebacks. I think we’ve all had points in our lives where we questioned our purpose and felt empty inside. Even the most chipper, the most arrogant, and the most ostentatious individual, has had a moment of quiet self-reflection. Especially if it was after something significantly impactful to their life had just happened.
You can see his reaction and the change in his whole demeanor in these panels (ONE does a surprisingly good job in displaying emotion or the lackthereof): (1) (2) (3)
This part in the manga was the final kicker for me that really disappointed me. Instead of being clearly despondent and looking like he’s had his whole life’s purpose taken away from him, he’s the same cocky brat. So since his inception in the manga, his character development went from cocky brat to… cocky brat. As you can see here.. There is no palpable change. Yeah sure, he’s beaten up. But he’s still the same edgelord. If you aren’t that affected from having your goals forever removed from your life, then your convictions weren’t even that strong in the first place. This doesn’t feel like a pivotal emotional moment in his life. At the end, he even cracks a wholesome smirk and says “you make me sick” to Saitama. This just comes across like every other tropey edgy character in animanga to make a character look cool, rather than an actual compelling character reaction. Another example of OPM doing tropes that it was meant to parody in the first place.
In the webcomic it felt like in the wake of the battle, Garou had to question the ethos of his entire existence. In the manga it feels more like a delinquent who had his naughty playtime ended. After all, in the eyes of others, this guy was just a ruffian who went around beating up people for no reason and ended up getting beat by the Invisible Man.
Manga Garou indeed did not have a moment after being punched where his viewpoint was questioned or a proper reason to all of the sudden turn from his ideas. He simply got one-shotted by Saitama, beat up by heroes (something that should reinforce his villainous beliefs), pleaded for dying due to his ideas, and then all of a sudden Tareo comes in and pointed out he saved him, and that is supposed to be the reason for him turning from his ideas. Manga Garou just stops being a villain just because, not because his worldview changed or was dismantled.