To be honest, I don't know where Liverpool got so much money, but Alexander Isak would be better transfer than Wirtz or Ekitike.
Isak is a magnificent striker who has performed excellently in the EPL, scoring more than 20 goals in the last two seasons, and the only thing that could deter Liverpool is the high transfer fee of £120-130 million.
However, Ben Jacobs writes that Liverpool is ready to sell Luis Diaz to Bayern for £80 million, which means Liverpool could find the money for Isak.
We know Liverpool have transformed from investment mode to fight mode so don't be surprised if they bring in new players with expensive labels. Several sources say that Liverpool's income continues to increase every season the same thing happens to their expenses this means they have calculated before making a decision when recruiting players. Did you know that Liverpool is in 5th place as the club with the most expensive squad value? so if they want to bring in new players then they can release other players well in this case as you said Luis Diaz is ready to be released to cover expenses.