As for Carroll, he was not worth the £35 million fee Liverpool paid Newcastle United to buy him and probably suffered from the same pressure that Benteke did. Carroll was never a prolific goalscorer (as proven by his subsequent moves to other clubs) therefore I have no idea why Liverpool chased him.
Back to the matter on hand. For tactical reasons, Isak will probably not be in my team.
One of the hottest at the time, and everyone was like, "If he's scoring this much here, imagine what he'd do in the Liverpool team." I'm not sure about the price, but he was literally the best ST at the time, and one could argue the price was justified. As long as Gakpo and Salah continue playing, I am fine with not joining the Isak ship anytime soon.
My only concerns are Dorgu and Rogers, but Aston Villa's SUN and BUR fixtures looks too good.