What da fuck are you talking about
In every combat sport there are fighters who can produce a fucking lot of power in almost every punch who can KO fighters from almost nothing
And you have fighters who can land a lot of hard punches, putting all his weight on it, and you can see they are trying to KO his opponent but they just can't
Boxing is much better to look at this, you can see a lot of interviews to some boxing legends and trainer, they always talk how some fighters hit you like a sledgehammer without even trying or without even putting so much weight behind it, some others can't produce any KO power.
Look at Ernie Shavers, Francis Ngannou, John Dodson, Johnny Hendricks, etc
In the right place, at the right moment anyone can KO anyone (Diaz vs Lawler, Bisping vs Rockhold), but everyone knows there are fighters that are consistently harder punchers