I believe it's because ONE and Murata realized the fight was incredibly lackluster on all fronts which nobody would ever admit until cosmic Garou happened.
It wasn't lack luster, but it did what they didn't do with Boros: They made Garou into a joke.
This also isn't me deep throating Boros (this time), this is something Murata mentioned
Murata: On occasion. For instance, during the big showdown with Boros. Since I felt this was the heavyweight championship of the universe, I tried to make it as flashy as possible. However, midway through when Boros starts losing ground to Saitama, there were places where he appeared clownish…ONE-sensei pointed out to me that the reason Boros is popular is because he always retains his dignity, even against Saitama. That made it all click for me, and I redrew things from square one. When it comes to the storyline, characters, and dialogue, all of that flows from ONE-sensei’s head, so I constantly check in with him.
Pre-CF Garou just didn't have any dignity. Saitama was dicking around incredibly hard against him and he was just a joke. Which is a factor in the backlash they got in my view.
the stakes already happened tho, if anything it builds more around just what is saitama even?
The point is that once you stop treating death as serious the readers will also stop treating it serious. Its one of the largest complaints about DC/Marvel and say, Dragon Ball.
Genos' death was a big event for Saitama, but it was quickly undone because they wrote themselves into a unfavorable situation.
but alot of the redraws built more stuff
A lot of the redraws drawed out a long arc to be even longer and most of them, like with Sweet Mask for example, probably didn't need to be done in the first place.
Other redraws like with Orochi just served as setup for future arcs and the entire Phoenix Man arc was just hyper cancer with the redraws.
when hes brought back more to his wc "self" they complained,
But the big thing here: They didn't do that.
WebComic Garou never killed any human. The entire twist was that his thing was a front because he wanted to be a hero. The manga tried to keep that twist, wasn't subtle, had him mind controlled by another character to kill dozens of others and then gave Saitama time travel to undo all of that.
Its not a 1:1 comparison here. You can like the manga while still noting its not perfect. The WebComic has its own pacing and writing issues when it comes to massive text dumps for example.