Liverpool lost several core players in this season's transfer window such as Firmino, Fabinho and captain Henderson. Now leaving these 3 players certainly leaves a gap for Liverpool management to be overcome immediately in this transfer window. We'll be looking forward to seeing what changes kloop will make in the one month remaining of the transfer window before it closes in September.
So if you look at Liverpool games in pre-season matches, of course they didn't show a more impressive performance when they faced Bayern Munich because it was clear that there were many gaps in weakness in their squad. Bayern munich was able to beat them even though they lost Sadio Mane, but Bayern Munich performance in this match was quite impressive. But for kloop he seems to have found a weak spot in their squad after being left out by Firmino, Fabinho and Henderson.
I wouldn't use preseason games to rate a team's performance in the in-coming season but it's obvious Liverpool needs more signings based on the numbers of players that have exited the club. I don't know what magic Klopp is going to perform, but for him to sanction the sales of these players he must also have a plan to bring in new faces. They've realize some money from player sales plus transfer budget, the only problem is there's limited time to bring in new players and blend them with the current squad in preparation for the new season.