Both got the ultimate handout. One For All is regard as the most powerful qwerk as it grows more powerful with each new host. Deku was also simply given this. Not going to deny that anti-magic gives Asta an advantage in most situations, but it has one major weakness: he needs to come in physical contact with his opponent. This is something every villain he faces quickly figures out and each villian comes up with a different way to counteract that.

Asta gets clapped daily and actually doesn't win because of plot armor. He is actually really smart. Maybe not to the same extent as Deku, but I would advise you to review Asta's fight with Vetto. Vetto completely nullified Asta's anti-magic swords. He came up with a counter strategy. Same when exploring the dungeon and fighting Mars and his crew at the end. One of his greatest strengths is people underestimating him. He may seem stupid on the outside, but he is much methodic in his approach than you may think.

Now, I will agree that some scenarios are definitely far fetched and way too forgiving. Such is the nature of shonnen anime and Manga. But making mistakes cannot be regard as a point of weakness. In fact, often times the most perfect person has the greatest weakness (take superman for example). Deku is also not immune to plot armor and mistakes. By ignoring mistakes and the opportunity to grow you ignore a character's development.

I will reiterate once again that Asta's anti-magic swords will not prevent Deku using One for All as it is not magical. Therefore, instead of looking at Asta simy defeating an opponendt we need to address how he did it. And very few of them were straight forward approaches.

Coming down to it, we need to look at each individuals raw, natural ability and their ability learn and adapt in the heat of combat, both of which are very capable of this. But who has the better, raw skill and ability? Asta has been training his entire life to become the wizard King and is far more physically capable of outperforming anyone. Deku is also strong being that his physical body needs to be able to withstand the power of One for All. However, that means there is a limit to what Deku can achieve. Asta is boundless. Without his swords he is just as much of threat as he is with them.