I understand Haaland's having some problems at the moment, but I think a lot of people are forgetting what Aguero's second season was actually like. We look back on him like he was perfect from the moment he arrived until the moment he left but that wasn't the case. He scored 30 goals in his first season and came up with massive moments in crucial games - his record was 0.63 goals per game. But in his second season he was carrying an injury, defenders in this country had adapted to his style, and his scoring rate dropped down to 0.42 goals per game. He had to shake things up to get better and he did, with his scoring rate jumping back up to 0.82 goals per game in the 13/14 season. From there he never looked back.
Seasons like this are the making of strikers because it's about how they learn from fallow periods. One big example I always come back to is Didier Drogba, who is a proper Premier League legend, a Chelsea legend, and is considered one of the greatest strikers to ever play the game. In his first two seasons he scored 0.39 goals per game. His best ever season for Chelsea (during his first time there) was the 09-10 season when he scored 0.89 goals per game. His next best is 0.55 goals per game, and his average during his Chelsea career was 0.46 goals per game. Currently Haaland is scoring 0.91 goals per game - this season he's scoring 0.79 goals per game. I think Haaland and the rest of our players could be doing more to work better together but he's not a major worry imo.