Also, about him changing things in the timeline... that isn't the initial point.
The problem in the old timeline was that he was inattentive and didn't speak up. It isn't conveyed here very well in the manga, especially because they skipped out on him meeting his waifu. I mean, he still is a normal human by the world's standards. He's no monster with cheats. All he has is his experience and desire to do a complete 180 by keeping a stronger connection and presence to the girl he loves, and speak openly and aggressively to people he hates rather than just being a manservant.
Yeah, he didn't go off and do something different but that was never what he wanted nor needed. His mistake in his previous life wasn't being associated with the Hero Party but being their dog.