It will not just damage their plans for the third time this season but it will also kill the plans Liverpool has for Alexander Isak. Newcastle United will not let go of Alexander Isak if they don't get a back up striker for him. That is something I love and I don't want Liverpool wrapping a deal for him. Also, Sesko comparisons to Erling Haaland makes no sense, let him be himself in the Premier League Competition.
Isak wants to leave Newcastle United and finds a new challenge and chapter for his career but surely he will look at a better club than Newcastle United. He will not have interests of joining Manchester United and remember that he is on transfer list of Liverpool. I believe between Liverpool and Manchester United, he will choose Liverpool and this club already sold Darwin Nunez to Al Hilal after buying Ekitike and perhaps they are preparing another slot for Isak.
Both Sesko and Isak are under quality compares to Haaland but Isak already played in Premier League several seasons and he is a safer choice for any big club than Sesko.