I was thinking the same thing as well, concerning how Liverpool will be able to cope without their hit player, I later realized that one thing with nature is that, nature will always fills every gap, might not be exactly the way you want it, but trust me it will be filled up. You can see that the other players have come to the realization that their hit player is not around, so they need to play to leave up to the expectation of the club and so far they've been doing very well. The players you mentioned in their last match, where very brilliant in their pattern of play especially Diogo Jota and Gakpo.
Liverpool have played 3 matches without their mainstay player and they managed to win all the matches including against Arsenal in the last FA Cup well, this can prove that Liverpool has a complete squad I mean other players can take the same role when the main player is not in the lineup, it's just that it would be better and greater if all the players were in line. Anyway, for now I don't have too many doubts about Liverpool even though their mainstay player is absent because there are still other great players ready to take over.