With a squad like Manchester City, Nunez might have scored a lot of goals. Not to say that the Liverpool squad is weak. However, since Sadio Mane left the team, Liverpool's performance has completely collapsed. And their performance was very erratic. Because of this, the team has not consistently performed better than Nunez. However, in the last few games of the season, Liverpool played very well and their performance was stable. Therefore, it is expected that Liverpool's performance will not be irregular in the next season. At the same time, Nunez will be able to score a lot of goals if he gets enough support from his teammates.
I too think Liverpool performance has dwindled after the departure of Sadio Mane to Bayern Munich and they haven’t quite recovered fully enough from it although we can’t actually classify them as a weak team. I still believe Darwin Nunez still has a role to play at Liverpool and perhaps doesn’t get enough support from his teammates like you noted.
With a squad like Manchester City, I believe Nunez would definitely have scored much more then he did. Nevertheless, the next season would probably be better for the lad and in general for the club if they could maintain some sort of consistency in their performances.
Mane's departure actually affected Liverpool's performance. in fact, I think it contributed to how poorly they started the season and their inability to make the Champions League. They signed multiple talents after selling Mane, but they still need time to settle in. Quality players Luiz Diaz and Nunez must still adapt in order to fill the void left by Mane. Mane made a significant contribution to Liverpool by supporting Salah and making their attacks more aggressive when he was present. Although Gakpo and Nunez need more time, I think they will hit their peak because they are talented.
Nunez will score in Liverpool as well so its not until he plays in a team like Manchester City, Liverpool is also an attacking team he got couple of chances and he missed most of them if not he would also be challenging Haaland for the highest goal scorer if he was as clinical in front of goal.