I don't think there is much wrong with Liverpool's current squad, of course the fans are waiting for a new star player to be added to the squad, maybe it could be because it would be an impressive innovation for the championship. But as you said the current squad is good enough to compete with Manchester City and Arsenal.
They played a very good game against Manchester United, Liverpool already gave good signals for the new season with a score of 3-0, so in the end the squad is the same and they are good to be honest.
The thing here is let Liverpool not get carried away by this wins against Arsenal and Manchester United, this wins aren’t important if you ask me, Arne Slot needs to look beyond This and strength the club, last season we all know how Liverpool struggled with few injuries and most of the season ended with young players been fiddled in tough games and it cost them the title. They are not ok like this as a squad if they wish to compete with Manchester city. One key area they seriously lack to me is the midfield area, they need reinforcements and it should be this season. Also a new striker like Isak of Newcastle wouldn’t be bad because the dependent on Nunez is just too much and it’s not going their way at the moment he needs competition