Liverpool performance in the previous season wasn't good globally and Klopp know that along with Liverpool's staff.
Until now in this winter transfer window, Liverpool recruited two attacking midfielders. Firmino who left them for free to join Al Ahli in Saudi Arabia league, left his spot to Darwin Nunez only, who should improve more and more to boost the team scoring ability. Mohamed Salah is the only right winger too but there is Gakpo who could play in this position too. I find the attacking line quite limited along with the number of players in Liverpool comparing to other teams.
I think Liverpool are in a transition period and they've actually been pretty good so far. After being left by Firmino who joined the Saudi league team, Darwin Nunez will now become the successor of the number 9 jersey at Liverpool and during this pre-season match he has proved enough of his contribution by scoring 3 goals in two pre-season matches. With this, we can see that Darwin Nunez is getting more productive and it is hoped that he will also bring this result later when the EPL competition starts. I think Liverpool still have good squad depth for that position and as back-up are Diogo Jota and Luis Diaz who are currently recovering from injury.