Yes, of course Liverpool supporters are starting to lose confidence in the change of coach that Liverpool is currently making, but a change of coach must always be done because there is no other choice and Liverpool supporters must believe that Arne Slot will be able to give his best even though he doesn't have much experience in the field.
Not only Liverpool fans, most football lovers look like not so confident with Liverpool anymore. Moreover, there is a rumor that Salah may leave Liverpool if there is an interesting offer for him. If Salah leaves Liverpool, I don't a chance of Liverpool to play better in the next season. Even if Liverpool may still stay in the top 5 of EPL standings, they are unlikely to compete for the title. Moreover, with a new coach, everything needs time for adaptation. They may experience a hard season.
Liverpool may see their performance decline slightly when they appear in the Champions League when they have to face other big clubs and also having to maintain their position in the Premier League will be a very big challenge for the new coach but we have to remember that Liverpool has reliable players who have great experience big so it can be relied on.
It is very possible to see a decrease of their performance next season. I don't expect much that Liverpool to go far in UCL. I just expect Liverpool can stay in the top 5 of EPL standings. With a new coach, the minimum target should be UCL zone. They surely won't try to target competing for the title in the next season.