ONE also writes the plot for the manga, he simply has Murata to draw for him, but not to write for him.
Everything that happens in the manga version is the author, ONE, deciding he prefers it going this way than what he originally wrote. Murata just adds the beautifully drawn cherry on top.
It really is too bad you don't like the changes, I know the feeling, it's happened to me in other adaptations, but I definitely do not share the feeling with OPM.
And regarding Dragon Ball... I like Dragon Ball, but it's not even a comparison. DB's feats are more about characters telling than showing the actual tangible feats, which is why Saitama vs Garou felt a lot more satisfying (and still fun) than usual DB fights. I actually saw Saitama being a casual world destroyer instead of needing to be told. And they even reset his powerlevel after the fight.