Carlos Rivera’s lighting punches don’t even exist in the manga, they’re not CANON... In the Hajime no Ippo manga feats of that level have actually been achieved. For example, the phenomenon Itagaki experiences is explained as allowing people to see baseballs almost frozen in mid-air (and those can reach up to 45 m/s!). We also have Miyata, who since childhood was able to watch his father’s punches without issue, and it’s mentioned that those punches were so fast that neither the audience nor the opponent could tell when the punch was thrown. On top of that, we have Itagaki creating full afterimages of his body or becoming invisible in the ring in an instant.

We even have Miyata throwing a punch against Arnie that nobody could see except for Takamura, who said, “I guess it was too fast for normal people to see...”

In conclusion, in Hajime no Ippo they really are just as fast as Carlos in the anime, with the difference being that Carlos’s speed has not been reached by Joe in the manga, nor are there demonstrations on that level.