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In statistics, there is such a technique - to cut off the upper and lower 5-10% of some data under study in order to remove the influence of anomalous fluctuations. If we remove the anomalous game with Bournemouth (9-0) from Liverpool's statistics, then Liverpool's statistics become faded and the goal difference is even negative. Therefore, I would say that Liverpool have problems with the attack too.
Almost forget about the 9-0 that Liverpool scored this season. At some point with all negative results, you just remember how much failure you see and the positive moments fade away.. As you said, if we remove that game, everything becomes worse, a lot!
It is difficult and complex to try to understand what's going on there. Most players dropped in performance? Mane absence impacted a lot the team? Concentration level is very low? A combination of all these in fact.
ManU was in the same situation or worst but at least they recovered from it. Liverpool doesn't seem to recover at all and I doubt Klopp will continue with the team.