I could be wrong but summing it up
1 The incredible effort to battle for the 4 titles last seasons is causing mental fatigue / physical issues this season.
2 Many major injuries all across the squad.
3 The failure by the club to adequately replace Coutinho then Wijnaldum, as a result almost every team parks the double decker against us, it is why we won the 2 cups last year on penalty shootouts. hell even Real did it in the final last year, didn't we have 23 - 1 shots at goal and they scored and won ?
If I was Jurgen Klopp I would demand this list of world class players from the owners, 1 Centre back 2 Attacking midfielders and 1 Holding midfielder, otherwise the future could become bleak.
From my perspective as a rival fan, your team just doesn't seem to have the same balance it used to have. When Thiago signed for you club I went back and forth in this thread with a couple of blokes regarding the shift in your system, and i think eventually that was Klopps biggest mistake.
At your best, you had three workhorse midfielders which shielded your defence and gave Trent and Robertson the ability to focus on their runs forward. You had a workhorse false nine midfielder who was willing to sacrifice his own stats to better two of the fastest wingers in Europe. You then signed:
Thiago - A finesse midfielder who has had a career interrupted with injuries.
Luis Diaz - A player who at that point was 24 and besides the year you signed him, had shown too many glimpses of poor finishing.
Konate - Has dealt with injuries since he debuted in professional football, only once played more than 21 games in a season before you signed him.
Nunez - Signed him at the age of 23 when he had only ever had one campaign of banging more than 15 goals (in all comps).
I rate all of these players as individuals, I think Diaz is one of the most exciting players to watch in the PL, and I think people have been too harsh on Nunez this year too, but the point stands, none of these players fit the profile of player that you had when you were flying between 2016-2019. Thiago isnt going to cover as much ground as Wijnaldum, Milner or Fabinho, which means Trent is called to defend more and therefore exploited. Diaz is fun to watch but he is the furthest thing from clinical which in reality is what you guys need to replace Mane. Konate has always been injured and no surprise he got injured a few times last year. Nunez is someone who needs to be leading the line, but then that leaves a big gap between your midfield and attack (where Firmino used to operate), and also leaves less room for Salah.
You had a perfect balance before and you shouldnt have tried to adapt as much as you did. Youre at a point now where the whole system must change to fit the new crop of players, and thats going to be one the biggest challenges in Klopps career to date.