As of now, Deku is very much alive in the manga. The plot hasn't reached a point where he meets such a fate. Usually, main characters like Deku have significant story arcs and aren't easily killed off.
The main differences are in their expressions and some minor details of personality. In the manga, Deku might seem a bit more intense, while in the anime, he's sometimes presented a bit softer.
In the manga, Deku experiences various ups and downs. He not only becomes stronger physically but also matures emotionally as he takes on greater responsibilities. There are also many unexpected plot twists that shape his journey.
In the manga, Deku's speed isn't constant. It improves as he gains more control and power. For example, in intense battles, he can move at impressive speeds to outmaneuver opponents.
Deku's speed varies depending on the situation and his development. Sometimes he can be incredibly fast, especially when he uses his special abilities.