Yeah, i have heard that too. Isaak's move to the Liverpool is most likely possible as he also wanted play for the reds. His problem is his club that is not willing to sell him. Money ain't the problem for his club, but selling him to the rival is gonna be their worst blunder.
He asked his team to explore the way he can move to Liverpool, but it most likely his club prevent it. He's still under long term contract with Newcastle, which is still three years away.
You're right, Isak has already told Newcastle that he wants to explore more and leave Newcastle. Of course, he's confident enough to do so because Liverpool are ready to make a bigger bid for him, even though they've already signed Ekitike. So, it's just a matter of Newcastle's future, perhaps waiting for them to secure another top player. And he's also a factor in Liverpool's success in selling Luiz Diaz.
But the question is, when Isaak does sign, will he be the main center-forward, or will Ekitike, who they just signed in this transfer window, be the first choice? At Newcastle, Isaak plays a key role and is a starting eleven.