Instead of comparing skills, I think it is way more productive to just list the characters feats and have people decide for themselves what is more impressive.
For Garou, his most notable skills include fighting analytical prediction and IR users in his sleep (Bang and Bomb). Copying techniques instantly and improving them while also simultaneously merging them with other martial arts in his sleep.
As Cosmic Garou, he his way superior to Bang who is comparable to, if not superior to Atomic Samurai, who is vastly more skilled than Iaian, who can predict 100,000 attacks coming at him from all directions with his eyes closed, relying on instincts, and while only having one arm.
Outside of that, he can also predict multiple attacks into the future against Saitama before he's thrown them. With Saitama, even casually, being able to blitz his eyesight. And he can predict various different potential attacks as well, shown as when he analyzed all of King's potential "next moves." Showing that he has great variation.
He can also merge techniques into his own on the fly and improve them to perfection past the original state of the technique. This also extends outside of martial arts as he quickly learned how to use Blast's portals extremely effectively just moments after copying them.
Adding onto this...
With the Bang fight, it is even more impressive than I give it credit for. Because during that Garou has to fight against Bang without being touched even a single time, otherwise his bones would be turned to dust by Bang's technique. Despite this, even in his sleep, he's able to adapt perfectly to this fact and use Roaring Aura Sky Ripping fist to deflect and counter attacks from Bang.
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Garou has assimilated the knowledge of countless schools into his martial arts, potentially meaning that he's also skilled in countless different styles of martial arts. He once read a scroll of "forbidden techniques" and from just one reading could mimic Explosion Release Fist. He's easily stomped groups of martial artists and other skilled fighters before through sheer adaptation. And he attacks using a synergy of every martial art he's absorbed, many of which are far beyond basic techniques and styles, such as WSRSF, or WICF... unleashing barrages of ever-changing attacks with all of them at once. He states himself that against his techniques, timing is essentially irrelevant. Take that as you will.
He also has developed this much mostly over the course of just two days. With a lot of it being within only a few hours. So there's no telling where he can really go if provided with even more content to evolve with...
While it isn't in the manga per say, I do also think it's worth noting that Garou as ONE envisioned can predict movements going off a number of different aspects, ranging from breathing energy to ones center of gravity. Whereas in the manga this is shortened to just him being able to predict ones next moves.
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Now... Regarding this fight...
I really honestly don't want this to be a skill debate.
I think they are each debatably more skilled than the other, but overall pretty comparable.
There's many other factors that can be debated here that are arguably more important.
It's possible Daewi might not even be able to counter the radiation 100% of the time.
It's also possible that Daewi uses some one-shot hax as a starting move.
Or that Garou manages to hit Daewi that one time and pulverize him.
For those reasons I support the decision of inconclusive but am willing to hear some further arguments.
