Isak is one of the best striker in the world currently and he's seriously being monitored by several clubs especially in the Premier league, I'm not very suprise that Liverpool are in forefront in his chase cause their key player Mo Salah could possibly switch to another club next summer and Isak is one of the players that's perfect for his replacement, Liverpool would be making one of the best signings of the summer if they could cough out such whopping amount for him and I think it's worth it since he's a player with great quality and has lots of experience in the league moreover signing a goal machine like him comes with lots of price. Well, Isak declaring his interest for then makes it more easier for Liverpool and I think the fee is not going to be a serious issue since Liverpool would cash in heavily on Mo Salah's sale if he leaves the club by summer.
Right now his scorer statistics underscore what you have said, but for Liverpool it will be more interesting to see whether he is going to score as much when he becomes a Liverpool player. You can see that some of the big transfers Liverpool made because those players scored a lot for other clubs eventually didn‘t pay off because they couldn’t do the same for Liverpool. It‘s quite a challenge for every player when they come into a new team where literally every position is filled with world stars. Competition within the team is tough and not scoring a goal for two games is worse in Liverpool than on Newcastle. Whether Isak is one of the best strikers in the world or not, that question would be answered if he can master the pressure there.