Of course, management and fans should give him time instead of having high expectations for him for the first season. Arne Slot is expected to be able to handle many of the things that have been obstacles for Liverpool in winning the title, but he must go through an adaptation process. Liverpool management must give him support, as do all the fans. Instant success cannot be expected, this applies to all coaches, although there are several coaches who managed to win the title in their first season.
The Champions League is certainly more difficult than the Premier League, so I don't think Arne Slot can be expected to win it in the first season. So I agree, give him time and be patient, Arne Slot will probably prove his worth in coaching Liverpool.
Yes, they have to lower their expectations of Liverpool a little because after all the new coach has to go through a process which will allow him to get to know his squad very well. Moreover, Liverpool has been with Jurgen Klopp for a long time, so perhaps it will take time for Arne Slot to implement the strategy he wants, because whether he likes it or not, if Jurgen Klopp has been in charge for a long time, what Jurgen Klopp implements will be attached to the team as a whole.
They have to give Arne a slot of time, they can't immediately give him a very high target in my opinion, because that would make them likely to make hasty decisions. They have to give opportunities like they gave Jurgen Klopp a chance, of course that has to be seen from the club's development. If there is a positive development, when they don't achieve anything next season then they have to give it another chance.