This is slightly wrong; why do i say so? Liverpool generally had a poor and inconsistent season; but their attackers did not underperform, instead Liverpool struggled in midfield and Defense and Klopp has been wise to work on those weakness in the summer transfer window.
Salah ended the season with 46 goal contributions, Darwin Núñez ended the season with 19 goal contributions, Gakpo has 10 goal contributions (joined in january). Klopp has done the needful with the Liverpool midfield, next season; the squad will flourish
Currently, Klopp is still monitoring the transfer market to see which players he can buy so he can make Liverpool stronger next season. Because Klopp still needs some great players for lines other than those occupied by Darwin Núñez and Gakpo so that they can create more valid collaborations within their squad next season. Apart from that, Klopp must also have a slightly different strategy from the previous season so that rivals can have a little difficulty reading Liverpool's style of play.
I don't think it was an issue that they had with strategies in their game. It was the lack of dedication and will power to achieve something. Strategy is one piece of a whole set of factors that make a team successful. Even if they had a good strategy, it wasn't the Liverpool that we are used to. Extremely aggressive and nonstoP pressing from the first minute till the last, high speed counter attacks and goal scoring efficiency. In the last season I could hardly see any of those things. They need to improve many aspects of their game and if the dedication comes back and the hunger for success, the right strategy is also important.